Conversions, Quantities, Calculations and Indulgences: A Primer

plant root carbon

Cross-section of a plant root, showing liquid carbon flowing to soil via the hyphae of mycorrhizal fungi. This carbon will support a vast array of microbes that not only retain carbon but also improve soil structure and soil tilth, enhance water-holding capacity, fix atmospheric nitrogen, solubilise phosphorus and provide minerals, trace elements and other growth stimulating substances to plants. Photo courtesy Jill Clapperton

Anyone attempting to make sense of calculations surrounding carbon cycling and soil carbon must first understand a little bit about quantities and conversion factors. Here are some basic facts you might find helpful.

Metric Conversions

First off, much of this literature uses the metric system of measurement. In case you forgot your high school lessons on the metric system, here are some useful conversions.

Length: one meter = 39.3701 inches; one inch (12 in. to a foot, 5280 ft. to a mile) = 2.54 centimeters

Area: one hectacre (10,000 square meters) = 2.4711 acres; one acre (43560 sq. ft.) = .40469 hectares

Volume: one liter (1000 cubic centimeters) = 1.0567 US quart (liquid); 1 US quart (liquid) = .94635 liters

Weight: one kilogram = 2.2046 lbs; one pound = .45359 kilogram

An additional complication concerns the use of the weight that derives from the ancient Germanic term for a large cask, or tun. In the US, one (short) ton = 2000 pounds. The non-US “conventional” system, however, uses the British Imperial (long) ton of 2240 pounds. Lastly, the metric tonne is 1000 kg or 2204.6 lbs, very close to the Imperial or long ton.

Temperature: one degree Celsius = 1.8 degrees Fahrenheit; 1˚F = .556˚C, water freezes at 32˚F or 0˚C.

Quantities

Carbon and Carbon Dioxide: The carbon atom has an atomic weight of 12. Carbon dioxide (CO2) is a molecule composed of a carbon atom and two oxygen atoms. Since each oxygen atom has an atomic weight of 16, the total CO2 molecule has an atomic weight of 44. Thus one carbon dioxide molecule weighs 3.67 times as much as a carbon atom, and carbon weighs .273 times as much as CO2.

People are approximately 18% carbon by weight. Wood is roughly 50% carbon, and soil organic matter is about 58% carbon. Typical soils, depending on level of compaction, weigh between 1200 and 1600 kilograms per cubic meter.

Before the industrial revolution and burning of significant amounts of fossil fuels, scientists estimate that the level of carbon dioxide in the atmosphere was 280 parts per million. We are now at 393 ppm. Anything beyond 350 ppm is considered unsustainable as it will heat the earth (greenhouse effect) beyond tolerable levels. One part per million of CO2 in the atmosphere is equal to 7.8 gigatons (GT or billion tonnes) of CO2 or 2.125 GT of solid carbon (for illustration, this is about a cubic kilometer of graphite).

Methane: This is a gas with the chemical formula of CH4. It is the main component of natural gas and a potent greenhouse gas, one unit trapping as much reflected sunlight as 25 units of carbon dioxide. It is produced by anaerobic respiration from bacteria, termites, and in the rumens of ruminant animals such as cattle.

Nitrous Oxide: This is a gas with the chemical formula of N2O. It is known as “laughing gas” due to the euphoric effects of inhaling it. Nitrous oxide gives rise to NO (nitric oxide) on reaction with oxygen atoms, and this NO in turn reacts with ozone. Considered over a 100-year period, it has 298 times more impact (global warming potential) per unit mass than carbon dioxide.

Note: When encountering calculations involving Methane and Nitrous Oxide, some writers will automatically convert them into their CO2 greenhouse gas equivalents (i.e. equate a methane molecule to 25 carbon dioxides, and a nitrous oxide one to 298 carbon dioxides). Be ready for these molecules to show up as CO2 conversions, without clear explanation.

Calculations

We can now calculate how much carbon is contained in an acre of top soil when that top soil is 6 inches deep and has an organic matter of 1%. We can also calculate how much carbon dioxide that carbon is sequestering.

Taking an average soil weight of 1400 k/m3, the top inch of a square meter of soil will have a weight of 1400 kilograms divided by 39.3701 (inches in a meter) or 35.56 kilograms, and the top six inches will have 6 times that much, or 213.36 kilograms. If the six inches of top soil in a square meter weighs 213.36 kg, by the magic of the metric system we see that the weight of a hectare of that top soil is 2,133,600 kg. But we want to know about an acre of it, so we divide by 2.4711 and find the answer is that 6 inches of top soil weighs 863,421.1 kg per acre. Now only 1% of that is soil organic matter (SOM), so we now have 8,634.211 kg of SOM. And only 58% of that is carbon, so we are down to 5,007.8 kg of carbon.

That is pretty close to 5 tonnes (metric tons) of carbon, so lets call it that. Since all that carbon was put there by the magic of photosynthesis – the plant using sunlight to combine carbon dioxide (CO2) from the air with water (H2O) from the soil to make carbohydrates (usually with the form Cm(H2O)n where m could be different from n ) for the plant and giving back oxygen to the air – we know those 5 tonnes of carbon came from 3.67 times as much carbon dioxide. So the answer, dear class, is that the acre of top soil with 1% organic matter has sequestered 18.35 tonnes of carbon dioxide.

Indulgences

That’s no slouch of a number. The average US citizen’s share of emissions, with all our fossil fuel addictions, according to the United Nations is less than that much carbon dioxide annually (17.5 tonnes to be exact.) Of course the average Bangladeshi emits 0.38 tonnes, and your typical Zambian manages only 0.19. But if you are looking for a way to assuage your guilt and justify your lifestyle to posterity, building a percent more organic matter in the top soil of an acre of your field or yard or community garden every year is not a bad way to go about keeping your head held high!

How does this calculation hold up for the task at hand globally? Hold onto your hats!

If we are at 393 ppm CO2 in the atmosphere now, and want to get back to the sustainable level of 350 ppm, we need to store 43 ppm somewhere. If each ppm is equal to 7.8 GT of CO2, we need to store a total of 7.8 GT times 43, or 335.4 GT of CO2. This may seem like a daunting task, even for organic farmers. But let’s do the numbers.

The land area of the globe equals 149.4 million square kilometers. If you take the 38% of that which the World Bank says is agricultural land, you have about 56.8 million km2. This, again by the magic of the metric system, is 5.7 billion hectares. One has to look up the conversion factor, of course, to find that this equals 14 billion acres.

If an increase in 1% of the organic matter of soil in an acre will sequester 18.35 tonnes of CO2, then 14 billion acres could sequester 256.9 billion tonnes. This is more than three-quarters of the CO2 that we need to sequester to get back to 350 ppm, the level of sustainability – all for increasing soil organic matter by one percent!

None of this, of course, would be easy. But isn’t it nice to know that soil can do that? It even turns out that with proper practices much of that carbon can be stored for centuries as humus. And the best part of it is that doing all this will improve the fertility and water retention capacity of your fields, give you better crops and make you more productive as a farmer.




Soil, Carbon, and How Plants Will Save The World

More and more agricultural scientists are beginning to recognize that there is a wondrous world just beneath our feet. We know very little about it, so far. But what little we are learning is staggering.

The rhizosphere (the narrow soil area immediately surrounding plant roots) is a densely populated zone where plant roots must compete with invading root systems of neighboring plants for space, water, and mineral nutrients, and with other soil-borne organisms, including bacteria and fungi. Root-to-root and root–to-microbe communications are continuous occurrences in this biologically active soil zone. How do roots manage to simultaneously communicate with and influence neighboring plants and symbiotic and pathogenic organisms within this crowded rhizosphere? Increasing evidence suggests that roots constantly exude chemicals that initiate and manipulate biological and physical interactions between roots and soil organisms, and thus play an active role in such communication and influence.

Green plants jumpstart the process using their chlorophyll and sunlight to magically create carbohydrates out of carbon dioxide and water. They use some of these sugars as the building blocks for further transformation into proteins, fats, antioxidants and phyto-chemicals of all sorts for their own growth and development. But a lot of the sugars, amino acids, proteins, organic acids, phenolics, and various other secondary metabolites will be exuded by the plant’s roots into the surrounding soil as a way of ‘hiring help’ from bacteria, fungi, and countless other organisms in the soil community.

Such services as accessing minerals and water, fighting off attack by disease organisms, repelling predators, and inhibiting competition with other plants can often be done more efficiently by various non-photosynthesizing organisms which, in turn, need the carbohydrates and other root exudates of the plants for their own survival. The co-evolution of plants with the many specialized soil organisms which provide these services is one of the more fascinating fields of study just emerging for young biologists!

In this fashion sometimes as much as half the carbon a plant draws from the atmosphere will ultimately be exuded underground and enter the bodies of microbial organisms. While some of that is ultimately oxidized and released back to the atmosphere when those organisms die, some is further processed into complex humic compounds, capable of resisting oxidation and of enduring for centuries underground.

It is this process of drawing in carbon dioxide as a gas, and pumping that carbon underground as liquid carbon compounds, which has tied up carbon in the past and can continue to do so in the future. As you will see when you read this issue of The Natural Farmer, it is the only process that has any chance of counteracting the increasing CO2 our combustion of fossil fuels is adding to the atmosphere.

To enable this process to deal with that much carbon dioxide, however, we need to enlist the aid of worldwide agriculture. The things which disrupt that process are bare soil which is not photosynthesizing, tillage which shreds fungal and other life forms vital to preserving soil carbon, and synthetic fertilizers (particularly nitrogen and phosphorus) because of their toxic impact on decomposer organisms. The ways to accelerate that carbon-fixing process are use of perennial crops and grasses, no till growing methods, biodiverse cover crops, livestock grazing, and the addition of stable carbonaceous materials (such as biochar) to soils.

In this issue we present what we hope is useful (and hopeful) information about soil and carbon. Every grower, whether raising annuals, perennials, or grazing animals, can adopt these methods and not only raise better and healthier products as a result, but also help nature take carbon from the air and return it to the soil.




Organics and Soil Carbon

Use plants to grow soil carbon

1. Use plants to grow soil carbon. The most economical and effective way

This paper explains how atmospheric carbon is introduced into the soil and how it is stored in stable forms. It identifies the farming techniques that are responsible for the decline in soil carbon and gives alternative practices that do not damage carbon. Increasing soil carbon will ensure good production outcomes and farm profitability. Soil carbon, particularly the stable forms such as humus and glomalin, increases farm profitability by increasing yields, soil fertility, soil moisture retention, aeration, nitrogen fixation, mineral availability, disease suppression, soil tilth and general structure. It is the basis of healthy soil.

Organic agriculture also helps to reduce greenhouse gases by converting atmospheric carbon dioxide (CO2) into soil organic matter. Some forms of conventional agriculture have caused a massive decline in soil organic matter, due to oxidizing organic carbon by incorrect tillage, the overuse of nitrogen fertilizers and from topsoil loss through wind and water erosion.

Why is carbon important to productive farming?

Soil carbon is one of the most neglected yet most important factors in soil fertility, disease control, water efficiency and farm productivity. Humus and its related acids are significantly important forms of carbon. Below is a summary of the benefits of humus

Humus improves nutrient availability:
  • Stores 90 to 95% of the nitrogen in the soil, 15 to 80% of phosphorus and 20 to 50% of sulphur in the soil
  • Has many sites that hold minerals and consequently dramatically increases the soil’s TEC (total exchange capacity or amount of plant available nutrients that the soil can store)
  • Stores cations, such as calcium, magnesium, potassium and all trace elements
  • Prevents nutrient leaching by holding them
  • Organic acids (humic, fulvic, ulmic and others) help make minerals available by dissolving locked up minerals
  • Prevents mineral ions from being locked up
  • Encourages a range of microbes that make locked up minerals available to plants.
  • Helps to neutralize the pH
  • Buffers the soil from strong changes in pH
Humus improves soil structure:
  • Promotes good soil structure which creates soil spaces for air and water
  • Assists with good/strong ped (soil particle) formation
  • Encourages macro-organisms (ie earthworms and beetles etc) that form pores in the soil.
Humus directly assists plants:
  • The spaces allow microorganisms to turn the nitrogen in the air into nitrate and ammonia
  • Soil carbon dioxide contained in these air spaces increases plant growth
  • Helps plant and microbial growth through growth stimulating compounds
  • Helps root growth, by making it easy for roots to travel through the soil
Humus improves soil water relationships:
  • The open structure increases rain absorption
  • Water loss from run off is decreased
  • Humus molecules soak up to 20 times their weight in water
  • It is stored in the soil for later use by the plants.
  • Improved ped formation helps the soil stay well drained
The processes to increase soil carbon can be divided into three steps
  1. Use plants to grow soil carbon
  2. Use microorganisms to convert soil carbon into stable forms
  3. Avoid farming techniques that destroy soil carbon

1. Use plants to grow soil carbon

The most economical and effective way to increase soil carbon is to grow it. Plants get between 95 and 98% of their minerals from the air and water. If we look at the chemical composition of an average plant, Carbon, Hydrogen and Oxygen account for over 95% of the minerals. The remaining 5% or less come from the soil. These minerals are combined using the energy of the sun via photosynthesis to produce the carbon based compounds that plants need to grow and reproduce.

The ‘Carbon Gift’ – how plants increase soil carbon

It is estimated that between 30-60% of the atmospheric carbon dioxide (CO2) absorbed by plants is deposited into the soil as organic matter, either in the form of bud sheaths that protect the delicate root tips or as a range of other root excretions.

These complex carbon compounds contain the complete range of minerals used by plants and are one of the ways that minerals are distributed throughout the topsoil. They feed billions of microbes – actinomycetes, bacteria and fungi that are beneficial to plants. Research shows that the greatest concentrations of microorganisms are found close to the roots of plants. This important area is called the Rhizosphere. These organisms perform a wide range of functions from helping to make soil minerals bioavailable to protecting plants from disease.

Research has shown that plant roots put many tonnes of complex carbon molecules and bioavailable minerals per hectare into the soil every year and are a very important part of the process of forming topsoils and good soil structure.

This means that well managed plants can put more bioavailable nutrients into the soil than they remove from it. Also the nutrients they put into the soil are some of the most important to the crop, to beneficial organisms and to the structure and fertility of the soil.

Managing weeds to increase soil carbon

If we look at weeds from this perspective, we can see that if we prevent the weeds from choking our crop, especially from getting the important sunlight, they can be increasing the fertility and health of the soil and actually helping our crop, rather than hindering it.

If the weeds are managed properly, and their residues are allowed to return to the soil, their nutrient removal from the soil is zero. In fact, as they are adding between 30% to 60% of the organic compounds they create through photosynthesis into the soil, they are increasing soil fertility.

Studies of weed fallows and the microorganisms that they feed show that they help with increasing the bioavailability of the minerals that are locked into the soil. Soil tests show an increase in soil fertility after weed fallows and when plants are grown as green manures. It is one of the reasons why ground cover fallows restore soil health. They return tonnes of carbon into the soil, feed the microorganisms that make nutrients bioavailable and reduce soil pathogens.

The important thing is to ensure that the soil has adequate levels of all the minerals and moisture necessary for growth and that the weed management practices allow the crop to be the dominant plants.

Techniques are encouraged where weeds are cut down, pulled or grazed so that their residues will return to the soil will feed the crop. Cutting and grazing plants will result in significant percentages of roots being shed off so that the weed or cover crop plants can re-establish an equilibrium between their leaf and root areas.

These cast off roots not only add carbon and feed the soil microorganisms, they release nutrients to the crop and significantly lower nutrient and water competition. This addition of nutrients encourages the crop roots to grow deeper in the soil, below the weed roots resulting in larger crop root systems and better access to water and soil nutrients.

With these techniques, we are actually increasing the efficiency of the farm surface area capturing sunlight and using photosynthesis to make the carbon based molecules that eventually result in the fertile soils that feed our plants.

It is the nutrients that we lose off farm, either through selling the crop, through soil leaching or erosion, that need to be replaced every year. Good fertilization should always ensure that our soil has the optimum level of all the necessary minerals. If we do not replace the minerals that we remove from our soil when we sell our crop, we are mining our soil and running it down.

One of the reasons why good organic farmers notice that weeds do not become a problem in their systems is because they ensure they have excellent soil nutrition and health by using weed management techniques that build up the soil. The process becomes one of effective weed management rather than weed eradication.

One of the problems with herbicides is that by killing the ground cover plants, they stop the food supply that feeds these beneficials, thereby lowering the count of beneficial species. Consequently soil borne pathogens like Phytophthora and Fusarium can take over, as the various species that kept them under control are significantly reduced.

2. Use microorganisms to convert soil carbon into stable forms

The stable forms of soil carbon such as humus and glomalin are manufactured by microorganisms. They convert the carbon compounds that are readily oxidized into CO2 into stable polymers that can last thousands of years in the soil.

Some of the current conventional farming techniques result in the soil carbon deposited by plant roots being oxidized and converted back into carbon dioxide. This is the reason why soil organic matter (carbon) levels continue to decline in these farming systems.

The other significant depository of carbon is soil organisms. Research shows that they form a considerable percentage of soil carbon. It is essential to manage the soil to maintain high levels of soil organisms.

Also it is essential that farming techniques stimulate the species of soil microorganisms that create stable carbon, rather than stimulating the species that consume carbon and convert it into CO2.

Creating stable carbon

Creating stable carbon

Creating stable carbon

The process of making composts uses microbes to build humus and other stable carbons. The microorganisms that create compost continue working in the soil after compost applications, converting the carbon gifted by plants roots into stable forms. Regular applications of compost and/or compost teas will inoculate the soil with beneficial organisms that build humus and other long lasting carbon polymers. Over time these species will predominate over the species that chew up carbon into CO2.

Regular applications of composts and/or compost tea also increase the number and diversity of species living in the soil biomass. This ensures that a significant proportion of soil carbon is stored in living species that will make minerals plant available and protect the health of the plants.

Composts bring a significant number of other benefits

Research shows that good quality compost is one of the most important ways to improve soil. It is very important to understand that compost is a lot more than a fertilizer. Compost contains humus, humic acids and most importantly a large number of beneficial microorganisms that have a major role in the process of building healthy soils.

Compost provides the following benefits:
Humus
  • Adds humus and organic matter to the soil
  • Inoculates soil with humus building microorganisms.
  • Improves soil structure to allow better infiltration of air and water.
  • Humus stores 20 times it weight in water and significantly increases the capacity of soil to store water
Nutrients
  • Mineral Nutrients
  • Organic based nutrients
  • Contains a complete range of nutrients
  • Slow release
  • Does not leach into aquatic environment
Beneficial micro-organisms
  • Supplies a large range of beneficial fungi, bacteria and other useful species
  • Suppresses soil pathogens
  • Fixes nitrogen
  • Increases soil carbon
  • Release of locked up soil minerals
  • Detoxifies poisons
  • Feeds plants and soil life
  • Builds soil structure

3. Avoid using farming techniques that destroy soil carbon

The continuous application of carbon as composts, manures, mulches and via plant growth will not increase soil carbon levels if farming practices destroy soil carbon. The following are some of the practices that result in a decline in carbon and alternatives that prevent this loss.

Reduce nitrogen applications

Synthetic nitrogen fertilizers are one of the major causes of the decline of soil carbon. This is because it stimulates a range of bacteria that feed on nitrogen and carbon to form amino acids for their growth and reproduction. These bacteria have a Carbon to Nitrogen ratio of around 30 to 1. In other words every ton of nitrogen applied results in the bacteria consuming 30 tons of carbon. The quick addition of these nitrogen fertilizers causes the nitrogen feeding bacteria to rapidly multiply, consuming the soil carbon to build their cell walls.

This process results in the stable forms being consumed causing a decline in the soil carbon levels. The best analogy is money in a bank. The addition of the large doses of nitrogen fertilizer is the equivalent of a large withdrawal.

Freshly deposited carbon compounds tend to readily oxidize into CO2 unless they are converted into more stable forms. Stable forms of carbon take time to form. In many cases it requires years to rebuild the bank of stable carbon back to the previous levels.

Ensuring that a carbon source is included with nitrogen fertilizers protects the soil carbon bank, as the microbes will use the added carbon, rather than degrading the stable soil carbon. Composts, animal manures, green manures and legumes are good examples of carbon based nitrogen sources

Where possible plant available nitrogen should be obtained through rhizobium bacteria in legumes and free-living nitrogen fixing microorganisms. These microorganisms work at a stable rate fixing the nitrogen in the soil air into plant available forms. They can utilize the steady stream of newly deposited carbon from plant roots to create amino acids, rather than destroying humus and other stable carbon polymers.

Carbon eaters rather than carbon builders

The use of synthetic nitrogen fertilizers changes the soil biota to favor microorganisms that consume carbon, rather than the species that build humus and other stable forms of carbon. By stimulating high levels of species that consume soil carbon, the carbon never gets to increase and usually continues to slowly decline.

The use of composts with microorganisms that build stable carbons will see soil carbon levels increase if the farm avoids practices that destroy soil carbon.

Reduce herbicides, pesticides and fungicide

Research shows that the use of biocides (herbicides, pesticides and fungicides) causes a decline in beneficial microorganisms. As early as 1962, Rachel Carson quoted research about the detrimental effect of biocides on soil microorganisms in her ground-breaking book Silent Spring. Since then there have been regular studies confirming the damage agricultural chemicals are causing to our soil biota.

Recently the work of one of the world’s leading microbiologists, Dr. Elaine Ingham, has shown that these chemicals cause a significant decline in the beneficial microorganisms that build humus, suppress diseases and make nutrients available to plants. She reports that many of the herbicides and fungicides have been shown to kill off beneficial soil fungi. These types of fungi have been shown to suppress diseases, increase nutrient uptake (particularly phosphorus) and form glomalin.

Glomalin is a stable carbon polymer that forms long strings that work like reinforcing rods in the soil. Research is showing that they form a significant role in building a good soil structure that is resistant to erosion and compaction. The structure facilitates good aeration and water infiltration.

Avoiding the use of toxic chemicals is an important part of the process of developing healthy soils that are teeming with the beneficial species that will build the stable forms of carbon.

Use correct tillage methods

Tillage is one of the oldest and most effective methods to prepare planting beds and to control weeds. Unfortunately it is also one of the most abused methods resulting in soil loss, damage to the soil structure and carbon loss through oxidation when used incorrectly.

It is important that tillage does not destroy soil structure by pulverizing or smearing the soil peds. Farmers should be aware of the concept of good soil ‘tilth’. This is soil that is friable with a crumbly structure. Not a fine powder or large clumps. Both of these are indicators of poor structure and soil health. These conditions will increase the oxidation of organic matter turning it into CO2.

Tillage should be done only when the soil has the correct moisture. Too wet and it smears and compresses. Too dry and it turns to dust and powder. Both of these effects result in long term soil damage that will reduce yields, increase susceptibility to pests and diseases, increase water and wind erosion and increase production costs.

Tillage should be done at the correct speeds so that the soil cracks and separates around the peds leaving them intact, rather than smashing or smearing the peds by travelling too fast. Good ped structure ensures that the soil is less prone to erosion.

Deep tillage using rippers or chisel ploughs that result in minimal surface disturbance while opening up the subsoils to allow better aeration and water infiltration, are the preferred options. This will allow plant roots to grow deeper into the soil ensuring better nutrient and water uptake and greater carbon deposition.

Minimal surface disturbance ensures that the soil is less prone to erosion and oxidation thereby reducing or preventing carbon loss.

Control weeds without soil damage

A large range of tillage methods can be used to control weeds in crops without damaging the soil and losing carbon.

Various spring tines, some types of harrows, star weeders, knives and brushes can be used to pull out young weeds with only minimal soil disturbance.

Rotary hoes are very effective, but should be kept shallow at around 25mm to avoid destroying the soil structure. The fine 25mm layer of soil on the top acts as a mulch to suppress weed seeds when they germinate and conserve the deeper soil moisture and carbon. This ensures that carbon isn’t lost through oxidation in the bulk of the topsoil.

There are several cultivators with guidance systems that ensure precision accuracy for controlling weeds. These can be set up with a wide range of implements and can be purchased in sizes suitable for small horticultural to large-scale crop farms.

Organic farmers in the USA, Europe and Australia are using these to get excellent control over weeds in their crops.

Avoid erosion

Erosion is one significant way that soil carbon is lost. The top few centimeters of soil is the area richest in carbon. When this thin layer of soil is lost due to rain or wind, the carbon is lost as well.

Avoid burning stubble

Practices such as burning stubble should be avoided. Burning creates greenhouses gases as well as exposing the soil to damage from erosion and oxidation.

Encourage vegetation cover

Vegetation cover is the best way to prevent soil and carbon loss. As stated in the previous section ‘Managing weeds to increases soil carbon’, it is not always necessary to eradicate weeds. Effective management tools such as grazing or mowing can achieve better long term results.

Bare soils should be avoided as much as possible

Research shows that bare soils lose organic matter through oxidation, the killing of microorganisms and through wind and rain erosion. Cultivated soils should be planted with a cover crop as quickly as possible. The cover crop will protect the soil from damage and add carbon and other nutrients as it grows. The correct choice of species can increase soil nitrogen, conserve soil moisture through mulching and suppress weeds by out-competing them.




Diversity is King

cover crop cocktail

Closeup of a cover crop cocktail comprised of Sorghum/sudangrass, hybrid pearl millet, cowpeas, soybeans, buckwheat, phacelia, hairy vetch, crimson clover, sunflowers, safflower, Winfred kale, Hunter turnips, brown top millet, persian clover. Photo courtesy Gabe Brown

The farm we’re on today was purchased by my wife’s parents back in 1956. They farmed conventionally — tillage, heavy tillage, half summer fallow, half small grains. They primarily grew spring wheat, oats, barley and, once in a great while, flax. So it was primarily cool-season grasses, half summer fallow, half crops. They also had a small cow/calf herd up until the late ’70s. In 1983 when I finished college, Shelly and I moved onto the place and entered the cow/calf business. Her folks were still operating the grain farming aspect of the operation and we did the cow/calf enterprise. Both my wife and I worked in town. During the late ’80s we started to divide up the pastures a little bit to do some rotational grazing as there were only three pastures on the operation when we arrived. That was our first foray, so to speak, into rotational grazing.

In 1991 we had the chance to buy the home place from them — they retired and moved to town. For the first two years I farmed conventionally with tillage. We’re in an environment where average precipitation here on the outskirts of Bismarck is about 15 inches, but of that about 9 inches comes as rainfall and the remainder is from snow. I always thought that moisture was the limiting factor in crop production on our farm. I had a friend in the northern part of the state who was a no-tiller, and he talked me into trying no-till to conserve moisture. He told me, “Gabe, if you’re going to go into no-till, sell all your tillage equipment. Otherwise you’ll be tempted to go back.” So I actually did that. We sold all of our tillage equipment before I bought a no-till drill in 1993. We bought a 15-foot John Deere 750 no-till drill, and we’ve been 100 percent no-till ever since.

The first year with that no-till drill I seeded some peas for the first time, and I began seeding some acres down to alfalfa. I started to diversify the crop rotation a little bit, but I didn’t have any idea where it would lead me. What really changed for us was in 1995. We had 1,200 acres of spring wheat — I should mention that the farm we’re on was about 2,000 acres of cropland with another 3,000-plus acres of tame and native pasture, so it’s a little over 5,000 acres altogether. The day before we were going to start combining the 1,200 acres of spring wheat we lost 100 percent of our crop to hail. That’s a pretty tough pill to swallow. Because it had only hailed once on this farm in the previous 25 years, we didn’t even think of taking out crop insurance for hail because it just never happened here.

You know it’s pretty bad when the USDA sends people out from the national office to take pictures. But I was already done combining peas before I lost my spring wheat crop, and that made me realize the importance of having a diverse crop rotation. After the hailstorm I decided that since we had those nutrients in the soil, let’s put some crop on there to grow forage for the livestock as, obviously that hailstorm also took all of our pasture. That was really my first try at what today we call cover crops. I went in and seeded some millet and some Sudangrass, just trying to grow forage.

In 1996 we started planting corn, and we planted more acres to peas. Obviously when you’re young and starting out and you lose the majority of your crop to hail, you have a tough time making payments. I couldn’t borrow as much money for inputs, so I wondered, “Okay, how do I supply nitrogen without having to purchase synthetic fertilizer?” So I seeded acres to alfalfa, more acres to peas and planted more forage crops such as Sudangrass and millet. I didn’t know at the time, but what I was really doing was laying the groundwork for crop diversity by diversifying the crop rotation. I had all these other crops along with spelt and spring wheat, oats, barley, and what happens but we lose 100 percent of our crop to hail again.

Well that was really devastating. My wife and I both worked off-farm jobs to help pay the bills. With two young children, things were tough. But after that second hailstorm I started to plant more mixes just to provide forage for the cattle. One of the combinations I tried was winter triticale and hairy vetch. At that time soil health was not even on my radar, I was just trying to save the farm. But really what I was doing was building a foundation for advancing soil health.

In 1997 we started to diversify the rotation even more but that year was a total drought — nobody around us combined an acre, including us. We had three years of crop failures in a row. I started planting more of the warm-season species crops — Sudangrass and millet, and I added cowpeas because I couldn’t afford to buy nitrogen, but I knew that if I grew a legume with these species, it would fix nitrogen for those grass species. So we started to grow some crops in combination. 1998 came along and we lost 80 percent of our crop to hail again. So I lost the majority of four crops in a row, and my wife and I will tell you that was absolutely the best thing that could have happened to us because it changed the way I looked at production agriculture.

I noticed that following the peas, the next crop was a little better. Following the diverse Sudangrass/millet/cowpeas, the next crop was a little better. Following the triticale/hairy vetch combination, the next cash crop there was a little better. We started to notice our organic matter percentages improving, and I should note that we were fortunate that we were soil testing. My father-in-law had soil tested for years, and I soil tested so we had the baseline data. When we purchased this operation our organic matter levels were 1.7 to 1.9 percent.

Those levels are typical of land that has endured a consistent regimen of little besides synthetic nitrogen for decades. And it’s more so indicative of the tillage and of lack of diversity in the cropping system. Those two things especially cause the degradation of soil organic matter. So our crop land was 1.7 to 1.9 percent. I noticed after four years of drought and hail that we were still able to inch that up. Obviously at that time I didn’t realize what I was doing, but today I know I had more roots in the ground. Approximately two-thirds of your organic matter increase will come from roots. Well, by growing all these cover crops, adding this diversity into the crop rotation, we were seeing an increase in organic matter, so that was a good thing. I had severely cut back on my use of commercial or synthetic fertilizer, and today I know that benefits soil biology. Back then I had no idea. I was just trying to survive, to feed the livestock, to produce something that would generate cash flow. That was it. Back then I had no inclinations as far as advancing healthy soil. I didn’t realize at that time that my soils were in a degraded state.

We ran 100 to 150 cow/calf pairs back in the mid-‘90s. Just as a point of reference to where we are today, on basically the same land base we now run 350 to 400 cow/calf pairs. That’s a constant. We keep our cow herd levels the same, and then we run anywhere from 300 to 600 yearlings on the same land base. We finish some of them on grass, so we’re actually keeping some of those animals until they’re 28 months old. We have significantly more livestock, plus we have a small flock of sheep, and we’re running pastured poultry. My son has an egg-laying business with pastured laying hens, and we have a few turkeys. We’ve really diversified the operation tremendously on that same land base. I just received my latest soil tests last month, and our organic matter levels were from 5.3 to 6.1 percent on those same fields that once were 1.7 to 1.9. So we’ve more than tripled our organic matter levels.

grass finishing steers

Photo of steers that Gabe was grass-finishing on a similar mix as illustrated below. Photo taken in September, courtesy Gabe Brown.

When we purchased the operation I was very fortunate that the USDA’s Natural Resources Conservation Service came out and did a soil infiltration study. What they found is that we could only infiltrate half an inch of water or moisture per hour. And that was because of all the heavy tillage and the lack of soil aggregation and pore spaces. The last test they did at my place over a year ago indicated that we can infiltrate over eight inches per hour. That’s a 16-fold increase. I tell people that even though we’re in what some might consider a moisture-challenged environment at 15 inches, it doesn’t matter how much rain you get, it’s how much can you infiltrate into your soils and then how much you can store. It’s the organic matter that improves the water-holding capacity of the soil. For every one percent increase in organic matter, that results in approximately 20,000 gallons more stored water per acre. So when my soils jump from less than 2 percent to 6 percent, think of how many thousands of gallons of water I’m able to store in my soil. And that’s just from a moisture standpoint.

After 1998 I had lost four crops in a row to hail and drought. We were able to hold on to the beef cow herd, and I was very fortunate that the bank did not foreclose on me. We were still able to make our interest payments, so they stuck with us. I had begun to see a real change in the soil.

It was about then, 1997 actually, when I was first exposed to holistic management. I heard Don Campbell from Alberta talk about holistic management, and that got me thinking about making my operation function as a whole. So often in agriculture today we segregate the corn crop from the soybean crop and segregate that from the livestock enterprises — everything is segregated. I got to thinking about the changes I’d seen in my operation having to do with diversity; it really struck home that what I was trying to do was imitate native rangeland. When you go out in true native rangeland, it’s very diverse. My son teaches range management at the local college, and once he brought his students out to one of our native pastures and in two hours they counted over 140 different species of grasses, forbs and legumes. That’s tremendous diversity. Don Campbell talked about holistic management, about how everything works together and how you can’t change one thing without affecting another. The hail and drought made me diversify my crop rotation by growing forage crops — Sudangrass, millet, cowpeas — I was putting livestock back out on the cropland. For me that was really the foundation of holistic management.

So from the late ’90s to right after the turn of the century, I expanded the use of cover crops on my system, and by that time I called them “cover crops.” Whenever I harvested a pea crop, for instance, I always immediately seeded something else. I started to read a lot about soil biology and what happens in the ground. We never used to see an earthworm on our land. Then the combination of no-till, cover crops and the residue I left on the surface to protect the soil had us seeing earthworms in all our fields. I was fortunate, too, when our district soil conservationist at the NRCS, Jay Fuhrer, took an interest in what I was doing and asked me to serve on the soil conservation district board. As a board we really delved into soil health. It was then that no-till took off in our county. I was one of the first no-tillers in the county. Today, Burleigh County is at least 75 percent no-till.

We saw a real expansion of people interested in no-till. Then in 2003 I had the good fortune of meeting Dr. Kristine Nichols, who came to work as a soil microbiologist with the ARS station in Mandan, North Dakota. Dr. Nichols did some of the original work on glomalin with Dr. Sarah Wright out of Beltsville Maryland. Dr. Nichols came out to my place in 2003. She walked in my fields and said “Gabe, you’ve come a long way but your soils will never be sustainable unless you remove synthetic fertilizer completely.” By then I had backed way, way off my synthetic fertilizer usage, but I was still using some.

So from 2003 until 2008 I did split trials in several fields on our operation. I would put down some synthetic fertilizer, albeit at a much a lower rate than recommended, and then on the other half of the field I’d put no synthetic fertilizer. For four years in a row, the unfertilized yields were equal to or greater than the fertilized. The last year we used synthetic fertilizers on our own land was in 2008, yet my yields have significantly improved. Another big learning curve moment happened in 2006 when I spoke at the No-till on the Plains conference in Salina, Kansas. Dr. Ademir Calegari from Brazil also spoke at that conference. He talked about these cover crop cocktails or polyculture cover crops in Brazil where they mix many species together. I was growing two- and three-way mixes, but Ademir was talking about seven-way mixes and above.

I came home and immediately started to diversify the cover crop mixes. That’s been a real learning curve in itself, finding out which species work best with each other. Nowadays, rarely do I seed a cover crop blend with less than 15 species in it. Most of the time there are at least 20 different species in a blend. I’ve found that we’ve really been able to increase organic matter and improve soil health. We get much greater production when we put these cover crops together.

The next big learning moment in my journey happened in 2006, up in Brandon, Manitoba at a grazing conference. A gentleman came up after my talk and said I had to see what he’s doing. It was Neil Dennis from Wawota, Saskatchewan. Neil is a mob grazer. Now at that time we had already ratcheted up to what I considered high stock density, 200,000 or 300,000 pounds of liveweight animals on an acre. We moved our cattle once per day. But Neil said we needed higher stock density, and we needed to move them more often. That spring I went up to Neil’s because I had to see for myself because I just didn’t think there would be much difference between moving them once per day and moving them several times per day. After seeing what Neil was able to achieve soil health-wise with these higher stock densities of 600,000 to 700,000, even 1 million pounds of beef on an acre, I came home and told my son this was the next step in soil health for us, but not only on pastures; we were going to do it on the cover crops.

You look at how these prairie soils were formed, with large herds of grazing animals, bison, elk, and deer, moving across the prairie, trampling litter down onto the soil surface. They left their dung and urine and then moved away, not to return for maybe a year. I wanted to mimic this on my cropland because Neil had proven it could be done. Allan Savory of course had proven it could be done on rangeland, but I didn’t see anybody doing it on cropland. I got to thinking about all these cover crops I’m growing, and what we lack in for improvement of soil health on cropland is the livestock component, so I came home and my son and I immediately started growing these cover crops, putting high stock densities, 600,000-700,000 pounds of beef, live weight, per acre on this cover crop and then rotating them. What we’re seeing is an absolute jump in the health and improvement of our soil resources.

We’ve been able to document this with Dr. Ray Ward at Ward Labs in Kearney, Nebraska, and Dr. Richard Haney, who is a soil scientist with the ARS station in Temple, Texas. Haney has developed a test that doesn’t only take into account the chemical and physical properties of the soil, it takes into account the biological processes happening in the soil.

Dr. Haney and Dr. Ward just formed an agreement and are now doing the test. I believe it costs $49.50. It’s called the Haney test, and it’s available commercially through Ward Labs, which is really exciting. The beauty of it is that it shows the one thing I think has been missing in production agriculture for many years. We know that after a legume crop you get a nitrogen credit, but no test out there has really shown the amount of nutrients that we can expect from the biological activity in the soil. The Haney test does that now — it is giving a credit for the biological activity. There are some specific protocols you need to follow in taking the soil sample. I see this as a huge step in cutting back the use of all of these inputs and fossil fuels in production agriculture.

Over the past several years we proved that by bringing cattle onto this cropland we’re able to take organic phosphorus and other elements ordinarily not available to plants and make them available. Because of this our proven corn yield now is 127 bushels per acre. That may not seem high to some, but the county average in Burleigh is under 100, so I’m over 25 percent higher than that, yet I have zero fertilizer cost. I have no fungicides, and I have no pesticides. We’re down to about one herbicide pass every two to three years, depending on the crop rotation and which fields we’re using. I tell people I’m striving to get to where I eliminate all my herbicide uses totally, but I will not use tillage to do that. To me, tillage is just too detrimental to the soil health.

I think we can build topsoil much faster than some scientists suppose, especially when we practice holistic management — integrating livestock, cover crops and diverse crop rotations. Glomalin is the glue that holds these soil aggregates together. We’re able to see on our operation that as we increase organic matter we’re building new topsoil. I was familiar with it but once Dr. Nichols came out here then of course my learning curve jumped. I tell people I’m really not that intelligent of a person, I just had the good fortune of meeting a lot of different key people at the right times to influence our operation, and then it was just a matter of my family and me taking the information we received from all these people and putting it to work.

The one thing that probably influenced me more than anything was Thomas Jefferson’s journals. Jefferson, on his plantation, talked about using crops such as hairy vetch, radish and turnips. Back then he was doing all the things I’m doing now. I tell people I’m not ahead of the game; I’m really several hundred years behind. It’s just that agriculture went full circle. That probably influenced me more than anything because I looked at how production agriculture took place years ago before they had synthetic fertilizers. Four years of financial hardships forced me to go back to those methods. Now I fully believe that it will be the wave of the future for production agriculture. Let me explain why: I spend a great deal of time in the winter traveling around the United States, Canada and other countries speaking about what we’re doing on our operation. I show them my cost of production to produce a bushel of corn. This past year in 2012, my total cost of production to plant the corn, harvest it, store it, haul it to market, land cost, equipment cost, everything, was $1.42 a bushel. I tell people corn can drop to $2 a bushel, and I’m still going to make money.

I spoke in Indiana this past winter and a banker came up to me after he saw that slide. He said, “Gabe, if corn drops below $5, half of my borrowers won’t be able to make their payments.” I thought, wow, look where we’ve gone in production agriculture. We’re so reliant on synthetic inputs. If we would do away with that and focus on soil health, we would lower the cost of production. I’ve proven it on my operation, and there are many others around the country. Look at what David Brant is doing in Ohio — consistently growing 220 bushel corn with no synthetic inputs, just cover crop usage.

earthworms in soil

Gabe holds some of his soil in his hands. Earthworm counts this spring averaged
over 60 per square foot. Photo courtesy Gabe Brown.

So I know this can take place anywhere. It’s simply a matter of getting off that tractor and focusing on soil health. I tell people, “We have come, as producers, to accept a degraded resource” because all of our soils are degraded. My soils, even knocking near 6 percent organic matter, are still degraded soils because I have native prairie soils that are at 7.3 percent. I’m not nearly back to where we were before the native prairies were tilled. We as producers have to focus on regenerating our soils. I get so tired of the new cliché, “sustainability.” Why do we want to sustain a degraded resource? It makes absolutely no sense to me. We need to be regenerative. We need to regenerate our soils and build them for future generations.

We raise grass-fed beef and market that to consumers. I mentioned my son’s egglaying operation, and we have a pastured poultry operation. Everything coming out of those gets marketed direct. The grains we’re producing right now, because I’m not organic, are marketed by way of conventional means. We haven’t used glyphosate on our operation in five years — and I refuse to use it — and we don’t use any GMOs. I also refuse to use them. The majority of the grains are going into the conventional system. Now, I’m working on how to eliminate that last herbicide pass which I use every two or three years. When I can eliminate that then we will be into the organic system.

I probably average from 15 to 25 calls a day during the summer from producers around the country asking questions about what cover crop they should use. I always tell them I will not make recommendations on what to use on your operation, because honestly I believe people need to try for themselves. When I go out and speak during the winter, I always get asked, “Gabe, tell us some of your failures.” I say, “No, I’m not going to tell you my failures because they might not fail on your operation.” My son and I have a saying on our operation — we want to fail at several things every year. I’m serious about that, because if we don’t try new things, how do we know what’s going to work and what doesn’t?

For instance, a young producer from northeast Colorado came up to me a couple of years ago, and he said he’d heard my talk about diversity and thought it made sense, “but how do I get my father and grandfather to try something else?” I asked him about his crop rotation. He said, “Well, since 1927 we’ve never planted a crop other than wheat.” I thought, my goodness, now that’s dead soil. To answer your question, what did I recommend to him? Well, all that land has had is cool season grasses for almost 90 years. He needs to diversify. There are four main crop types. There is warm and cool season, broad leaves and grasses in each type. He has a cool season grass in wheat, so what we needed to do there was get those other three species. Obviously in northeastern Colorado it’s very hot and dry. Let’s go in there with species that can handle the heat. We went in there with cowpeas, a warm season broadleaf, and added to it sunflowers, a warm season broadleaf, plus sudangrass and millet — both warm season grasses. We also added into the mix some radish, which is a cool-season broadleaf, to get a deep taproot in there. When I work with producers, the first thing I do is ask them about their resource concern. In the Colorado gentleman’s situation, he had no diversity. Because of that we’re going to get a very diverse mix — we added several other things to the mix.

This year there are a lot of people in northern North Dakota with an excess amount of moisture, so they have all this trouble with water. That’s their resource concern — excess moisture. Okay, you have to plant something to use that moisture. Then you have to plant species that will improve the infiltration in your soil. You need those deep taproots — things like sunflowers and radishes. We have to be able to move that moisture throughout the soil profile.

When I speak back east there are a lot of people with heavy clay soil. Same type of thing there, they can’t infiltrate that moisture, they need to build soil aggregates. We need to go into those soils with deep taproots, but we also have to go into those soils to increase organic matter. You’re going to do that with things like Sudangrass, which has a very prolific root system. Phacelia is a broadleaf crop used widely in France, and it has a tremendous root system. Rye of course is good. Whatever your resource concern is, that’s going to dictate the mix and species of cover crops you use.

Of course it varies region to region in the country. Crops I can grow up here cannot be grown down south and vice versa, so we have to tailor it to each specific region of the country. Too many times people think of cover crops as a cure-all, kind of like making soup — you throw in whatever’s in the refrigerator. It’s not like that at all.

You really need to put some thought into it or it can backfire. I’ll give you an example of that. I had a call a year ago from a producer in South Dakota and he said, “Gabe, you’re that cover crop guy. I’ve got a problem here, and I want to know what you think.” He said he had a winter wheat crop on irrigation, had combined it, baled the straw and then seeded it to turnips and radishes before putting his cattle there in the winter. I said, “Let me guess, you have no residue and your soils are blowing?” He said, “That’s exactly right.” I told him it only makes sense. The nitrogen that was left from that wheat crop was absorbed by the turnips and radishes. When they break down they’re going to release the nitrogen, and that’s going to accelerate the decomposition of what little residue he had left. He’d just compounded the problem of erosion on his operation.

There are a lot of seed salesmen out there who are extremely good, but some are just out there to make money. You really have to be careful when you put these cover crop blends together because it can have dramatic impacts on your soil for years to come. Having said that, though, there’s much, much more upside potential from planting a cover crop than there are negative aspects of it. I strongly encourage everyone to consider planting cover crops. Just be careful and do some serious planning before you do.

The thing of it is every situation is unique, every person’s soils are unique, every person’s resources are unique, thus their crop rotations are different. Some have livestock, some don’t. It almost is to the point they have to be tailored individually to each person.

Yet it’s really not that difficult either. All we have to do is follow nature’s template. Nature’s template is a lot of diversity, and you have to integrate livestock. And along with livestock I don’t only mean cows and sheep, I’m talking about insects also. If we would just step out of the way and let nature take its course, there are so many symptoms that we producers wouldn’t be facing today. For instance look at fungicide use today in production agriculture — they’re using it like water. Most producers are spraying fungicides every year. Instead they should be asking, “What makes that plant susceptible to a fungus? Well, what makes it susceptible is probably a lack of micronutrients or a micronutrient tieup. Lots of times that’s directly related to the herbicides we use. If we would focus on soil biology and soil health, that soil biology would make those micronutrients available and you wouldn’t need a fungicide. I haven’t used a fungicide on my operation in well over a decade. That doesn’t mean I don’t have fungal diseases, but they never reach the point that they’re economically detrimental to me.

Another concern I have is with the use of insecticides. If producers would build the habitat for the predator insects to prey on those insects that are economically detrimental, they wouldn’t need to apply an insecticide. Instead we’re to the point in production agriculture where we’re only seeing monocultures — we have very little crop diversity, thus there’s no home where these predator insects can live. That’s one of the side benefits to these cover crops. When we design these cover crop mixes we’re always adding flowering species in there — one to attract the pollinators, two to be a home for these predator insects. My son and I always try really hard to focus on solving problems, not treating symptoms. In production agriculture today all we’re doing the majority of time is treating symptoms. If we would get to the root cause of the problem and focus on solving that problem, these symptoms tend to go away.

Monoculture is the original sin of modern agriculture. I’ve proven that time and time again. For instance, I mentioned growing triticale with hairy vetch. I had a field here a number of years where we ran out of hairy vetch seed. Part of the field was hairy vetch/triticale mix and the other part was just straight winter triticale. We took that off as forage the next spring, as dry hay, there was a 10 percent difference in crude protein. It was higher obviously where there was hairy vetch, the legume. It also yielded over 35 percent more. I mean it’s a win-win situation.

You look at the monocultures in production agriculture today, it doesn’t make any sense. Where in nature do you find a monoculture? Only where man put it. Now obviously there might be a little piece here or there that’s a monoculture, but I’m talking in general terms, you just will not find it. I honestly believe one of the biggest detriments to society today is the current farm program and RMA, the Risk Management Agency. They’re not allowing us to do intercropping, and we’re not allowed to grow cover crops with the cash crop. On our operation we try to never seed monocultures. We always want a diverse mix in every field.

But yet in saying that, it’s going to kick you out of crop insurance because crop insurance won’t allow it but I don’t care anymore. I don’t take out much crop insurance because to me I’m just betting against myself. I think I’ve built up enough resilience in my soil that I don’t need to take out crop insurance. We can weather droughts even though we don’t have any irrigation.

Some people ask if harvesting those diverse fields isn’t very labor-intensive? Sure it is, but that just comes down to planning what combinations you use. For instance, one I’ve been using for a number of years in my corn, I will have a low-growing clover in. That low-growing clover, whether it be a red clover or subterranean clover or something like that will stay below the ears of the corn, so it’s not going to interfere with harvest whatsoever. Last year for example we grew an oat crop with three types of clover seeded along with it. When I straight cut the oats the clovers were not as tall and the oats yielded 115 bushels per acre. I was left with a growing clover cover crop and a living root feeding soil biology.

There’s been some good work done by guys who are actually now growing peas and canola together because they’re easily separated. A good friend of mine, Owen Carnes up in Saskatchewan, is doing this with great success. He’s growing peas and canola using pretty much a full seeding rate on each and going in and combining it, then he’s able to run it through a cleaner and separate it out easily. It’s netting him substantially more dollars per acre than a monoculture.

The thing of it is we’re getting much, much more production per acre. I get really tired of the question, how are we going to feed 9 billion people by the year 2050? It is absolutely no problem whatsoever if we diversify. Just drive anywhere in this country; you’re going to see monoculture field after monoculture field. How many acres upon thousands of acres do you see with no fences on it? On our operation we grow a cash crop, we grow a cover crop, grass-finished beef might graze it, pastured poultry might graze it, and we have guys who are bringing in bees to take advantage of those flowers on that cover crop so we’re producing honey.

There are a myriad of opportunities if we stack enterprises. Why should we settle? I can use any example, but say for instance in the corn belt, why should we settle for just 200 bushels of corn off that acre? Why can’t there be livestock added on top of that? Why can’t there be a cover crop with bees on top of that? It’s foolish for us to even think that we’re not going to feed that many people. To me that’s just industrial agriculture fear-mongering, saying we have to keep with this current production model.

The current production model is broken. It doesn’t work. It’s one of just treating symptoms — input after input after input. I realize the past three or four years have been very profitable, even under the current industrial agricultural model, but we can have sustained profits where we have diversity. Then we can start producing more nutrient-dense foods that are going to take care of this health crisis that’s occurring in this country.

Acres, USA, is at www.acresusa.com



Building Soil Carbon with Yearlong Green Farming

The capacity for appropriately managed soils to sequester atmospheric carbon is enormous. The world’s soils hold around three times as much carbon as the atmosphere and over four times as much carbon as the vegetation. Soil represents the largest carbon sink over which we have control.

When atmospheric carbon is sequestered in topsoil as organic carbon, it brings with it a wealth of environmental, productivity and quality of life benefits. An understanding of the ‘carbon cycle’ and the role of carbon in soils is essential to our understanding of life on earth.

Building soil carbon requires green plants and soil microbes.

There are 4 steps to ‘turning air into soil’
i) Photosynthesis
ii) Resynthesis
iii) Exudation
iv) Humification

Root volume, rhizosphere surface area, exudation of carbon, microbial activity, humification and soil building are highly correlated with the perenniality and vigor of groundcover plants

Root volume, rhizosphere surface area, exudation of carbon, microbial activity, humification and soil building are highly correlated with the perenniality and vigor of groundcover plants

Photosynthesis is a two-step endothermic reaction (i.e. a cooling process) that takes place in the chloroplasts of green leaves. Incoming light energy (sunlight) is captured and stored as biochemical energy in the form of simple sugars such as glucose (C6H12O6), using carbon dioxide (CO2) from the air and water (H2O) from the soil. Oxygen is released to the atmosphere.

Photosynthesis requires 15 MJ (megajoules) of sunlight energy for every kilogram of glucose produced. If the same 15 MJ of incoming light energy makes contact with a bare surface, such as bare ground, it is reflected, absorbed or radiated – as heat, usually accompanied by moisture. The respective area of the earth’s surface covered by either actively growing crops and pastures, or bare ground, has a significant effect on global climate.

Resynthesis: Through a myriad of chemical reactions, the sugars formed during photosynthesis are resynthesized to a wide variety of carbon compounds, including carbohydrates, proteins, organic acids, waxes and oils. Carbon atoms can link together to form long chains, branched chains and rings, which other elements, such as hydrogen and oxygen, can join.

The energy captured during photosynthesis and stored in carbon compounds serves as ‘fuel’ for life on earth. Carbohydrates such as cellulose provide energy for grazing animals, the starch in grains provides energy for livestock and people. The carbon stored in previous eras as ‘fossil fuels’ (hydrocarbons) such as coal, oil and gas provides energy for vehicles, machinery and industry.

Exudation: Around 30-40% of the carbon fixed by plants during photosynthesis is exuded into soil to form a microbial bridge (to feed the microbes that enhance the availability of essential plant nutrients). In this way, actively growing crops and pastures provide ‘fuel’ for the soil engine.

Carbon compounds are essential to the creation of topsoil from the structureless, lifeless mineral soil produced by the weathering of rocks.

Organic carbon additions are governed by the volume of plant roots per unit of soil and their rate of growth. The more active green leaves there are, the more roots there are, the more carbon is added. It’s as simple as that. The breakdown of fibrous roots pruned into soil through rest-rotation grazing is also an important source of carbon in soils.

Humification: Adding organic carbon to soil is one thing, keeping it there is another. Organic carbon moves between various ‘pools’ in the soil, some of which are short lived while others may persist for thousands of years. Carbon additions need to be combined with land management practices that foster the conversion of relatively transient forms of organic carbon to more stable complexes within the soil.
In the humification process, soil microbes resynthesize and polymerize labile carbon (exuded from plant roots) into high molecular weight stable humic substances. Humus, a gel-like substance that forms an integral component of the soil matrix, is the best known of the stable organic fractions. Humification cannot proceed unless there is a continuous supply of ‘fuel’ for soil microbes. If humification does not occur, the carbon exuded from plant roots (or added to soil as plant residues or manure) simply oxidizes and recycles back to the atmosphere as carbon dioxide.

Humic substances have significance beyond the relatively long-term sequestration of atmospheric carbon. They are extremely important in pH buffering, inactivation of pesticides and other pollutants, improved plant nutrition and increased soil-water-holding capacity. By chelating salts, humic substances can also effectively ameliorate the symptoms of dryland salinity. Increasing the rate of humification has highly significant effects on the health and productivity of agricultural land.

Importance of soil fungi

Most perennial grasses are excellent hosts for mycorrhizal fungi, with up to 100 meters of microscopic fungal hyphae per gram of soil under healthy grassland. Glomalin, a glycoprotein (combination of protein and carbohydrate) produced by arbuscular mycorrhizal fungi, can persist for several decades and may account for one third of the stable organic carbon stored in agricultural soils.
Mycorrhizal fungi and glomalin production are inhibited by bare soil, intensive tillage, the application of phosphorus fertilizer and the presence of plants from the Brassica family such as canola, which do not form mycorrhizal associations.

Maintaining soil structure

‘Aggregation’ is part of the humification and soil carbon building process and is essential for maintaining soil structure. Glues and gums from fungal hyphae in the rhizosphere enable the formation of peds or lumps (which can be seen with the naked eye, often attached to plant roots). The presence of these aggregates creates macropores (spaces between the aggregates) which markedly improve the infiltration of water. After rain less water sits on the soil surface and waterlogging is reduced. As structure continues to improve, smaller and smaller aggregates are formed, along with soil mesopores and micropores, dramatically improving soil function, aeration, levels of biological activity and resilience.

Soil structure is not permanent. Aggregates made from microbial substances are continually breaking down and rebuilding. An ongoing supply of energy in the form of carbon from actively growing plant roots will maintain soil structure. If soils are left without green groundcover for long periods they become compacted and can blow or wash away.

Under bare fallow cropping systems or set-stocked annual pastures, the stimulatory exudates produced by short-lived plants are negated by bare earth at other times of the year. The result is a decline in levels of soil carbon, soil structure and soil function.

Soil building requires green plants and soil cover for as much of the year as possible. In grazing enterprises, rest-rotation grazing is absolutely essential. For crop production, the presence of out-of-season groundcover ensures stability, long term productivity and soil building rather than soil destruction.

Any farming practice that improves soil structure is building soil carbon.

Water, energy, life, nutrients and profit will increase on-farm as soil organic carbon levels rise. The alternative is evaporation of water, energy, life, nutrients and profit if carbon is mismanaged and goes into the air.

Yearlong Green Farming (YGF) is any practice turning bare soil into soil covered with green plants. YGF increases quality, quantity and diversity of groundcover in cropping, horticultural, forestry and grazing enterprises.

Many benefits of Pasture Cropping, for example, can be attributed to having perennial grasses and cereals together side by side in space and time. Ongoing carbon additions from the perennial grass component evolve into highly stable forms of soil carbon while the short-term, high sugar forms of carbon exuded by the cereal crop roots stimulate microbial activity.

As a bonus, regenerative farming practices such as Pasture Cropping result in the production of food much higher in vitamin and mineral content and lower in herbicide and pesticide residues than conventionally produced foods.

Rewarding farmers for Yearlong Green Farming practices that build new topsoil and raise levels of organic carbon would have a significant impact on the vitality and productivity of agricultural enterprises. YGF would also reduce evaporation and heat radiation from bare soil surfaces, reduce the incidence of dryland salinity and counteract soil acidity.

Under regenerative regimes, soil carbon and soil life are restored, conferring multiple ecological and production benefits in terms of nutrient cycling, soil water storage, soil structural integrity and disease suppression. Benefits extend well beyond the paddock gate. Improved soil and water quality are the ‘key’ to catchment health, while YGF represents the most potent mechanism currently available for mitigating climate change.

It’s about turning carbon loss into carbon gain.

Getting started in lifeless, compacted soils where the soil engine has shut down is the hard part. The longer we delay, the more difficult it will be to re-sequester soil carbon and rebalance the greenhouse equation.

Dr. Christine Jones is a groundcover and soils ecologist and is currently the Scientific Advisor on Plant Nutrition for the Australian division of Best Environmental Technologies. She will be speaking at NOFA/Mass events in Boston on Sep. 1, 2014 and in Amherst, MA on Sep. 2, 2014. For more info go to www.nofamass.org or contact Julie Rawson
at Julie@nofamass.org, or at 978-355-2853.




No-Till Vegetables at Tobacco Road Farm

Over the last twenty plus years of intensive vegetable growing at Tobacco Road Farm, we have constantly sought ways to improve the health and vitality of our crops and soils. Much of the land grows vegetable crops year round so the intensity of production demands very careful soil care. To this end, soil amendments, fertilizers, inoculants, and compost have been carefully selected and applied over the years in no small degree.

Years of tillage, however, had left the field with a soil structure that was lacking. To reduce tillage damage to soil, techniques and tools were introduced: chisel plowing with shallow roto-tilling, permanent wheel tracks, use of sweeps and points for primary tillage, increased use of cover crops, for examples. Even under this minimum tillage difficulties still presented themselves: poor soil structure with low fungal activity, low calcium levels and high nitrogen and potassium in tissue analysis, weeds proliferation — especially galinsoga, excessive soil drying during summer dry periods, along with insect and disease pressure.

Measures to improve these conditions came through extensive soil and tissue analysis along with traditional Biodynamic approaches. The real push to no-till, however, came from the recommendations of Korean Natural Farming (KNF). Korean Natural Farming is most commonly known for the use and practices around IMOs, of Indigenous Micro-organisms. The practitioners of KNF, however, also recommend that no-till techniques be utilized.

Some no-till practices have been used on the farm in the past such as seeding winter squash into a properly mown rye cover crop, or transplanting into heavily mulched soils, but it was clear that a much more versatile system would be needed for the intensive production of vegetables under complete no-till.

New arugula germinating with lack of competing weeds

New arugula germinating with lack of competing weeds

Over the last few years a system was developed on the farm which has proven to be quite successful. Ways to kill preceding crops and reduce their residues, achieve weed-free seed beds, control weeds, apply fertility, increase biological activity and diversity, seed appropriately, and allow for better interseeding of crop and cover crops were developed. The fields where this system was put into place were quite fertile, had few perennial weeds, and plenty of annual weeds. The various methods are still being fine tuned, but with a high level of success it does seem appropriate to share what has been done.

To begin, the first step is to chop the existing cover crop if the vegetation is large enough to require this. This is achieved through mowing with a rotary mower front-mounted on a BCS two-wheel tractor. Essentially a heavy duty lawn mower, this machine has a bagging capacity which allows for the gathering of weed seed heads if this is required. A regular lawn mower can also be carefully used. This mower grinds the vegetation into small pieces for easy digestion into the soil and aids in the overall mulch layering effort to reduce weed seed germination.

A sickle bar mower can also be mounted to the front of the BCS for mowing full vegetation or for conditions where slower decomposition of residue may be required. Though we have quite a few larger tractors, the lighter weight of the BCS, along with superior maneuverability have made it the machine of choice for this job. Other methods used to chop residue include hand tools such as the machete, scythe, or sickle. These tools need to be kept very sharp to be effective and are obviously much slower than the mowing machines, but occasionally have an appropriate use.

The next step after chopping the pre-existing vegetation is to kill its roots. From approximately May through September this is achieved through solarization with clear sheets of plastic in the hot sun. The plastic is laid upon the newly mown residue and secured with sandbags. Two days of sunny, roughly 80˚F+ conditions are usually sufficient. The solarization quickly kills annuals, however perennial roots are entirely resistant to such quick solarization and are manually removed.

Ring drag made on the farm, held higher or lower to adjust action.

Ring drag made on the farm, held higher or lower to adjust action.

The plastic is removed as soon as possible to avoid soil damage. It is often left over high tunnel or low tunnel covers, though large sheets of 4 mil. construction plastic are also used. These sheets are rotated in order to cover large areas. During the cooler months these roots are hoed with very sharp hoes just below the soil line. Simply mulching over the roots with the weed-free compost and/or chopped hay is also practiced. Occasionally young growth is flamed after rain or irrigation and vinegar sprays have also been trialed.

Once the previous vegetation has been destroyed the next step is to apply weed-free compost, if required. This compost goes a long way towards the burying of weed seeds and feeding the soil biology. The compost is prepared with high carbon materials, making it fungal friendly, and contains large amounts of silica as well as other added minerals. Biodynamic preparations are utilized

The basic ingredients are: cattle manure, weed-free farm residues, vegetable scraps from the local food co-op, hay, leaves, sawdust, woodchips, basalt dust, clay subsoil, and minerals like gypsum, hydrated lime, sea salt, sulfur, zinc sulfate and a very small amount of boron, molybdenum, and cobalt. The piles are turned a couple of times, then applied to the surface of the beds with wheelbarrows, a dump cart mounted on a Farmall Cub, or for wider beds straight from a pickup truck bed or with a manure spreader which straddles the beds. Since the material is applied to the surface of the bed, larger volumes of carbon in various forms are possible and beneficial for our conditions. Compost application definitely gives better seed germination, though it is not necessary at every seeding.

Following compost application, inoculant is applied to the bed surface. This is in the form of an IMO, which is cultured from forest microbes from the farm’s surroundings. The techniques are from Korean Natural Farming, manuals for which are available from Acres, USA. This inoculant looks like a compost and aids greatly in enhancing fungal and microbial activity. Other inoculants like EM (effective micro-organisms) may also be useful. Sometimes inoculant is not applied at all. The compost and inoculant are very sensitive to drying so should be carefully applied, seeded, and covered with mulch immediately.

Seed is often broadcast over the bed surface. This needs to be done very carefully to get an even spread. This allows for maximum coverage of the bed with vegetation, which increases overall photosynthesis and thus helps feed the soil life and increase yield as well as inhibiting weed growth. Crops and cover crops can also be interseeded at any time since the soil surface is generally weed free. This allows for crop mix combinations which can enhance soil life as well as yield. Transplants are also set into the bed, though often they are set after the mulching step described below.

The seed applied to the bed surface germinates better if it is worked into the soil surface. This is accomplished with the use of a drag, which is a group of chain rings attached to a bar. The rings are grain drill covering rings, purchased from Agri-supply company, and were not expensive. The drag is pulled one way over the length of the bed and then back the other way and is very quick and effective. A rake can also be used but it is much more difficult to achieve similar results with one. Another tool that is sometimes used for larger seed is a garden weasel, which resembles a hand pulled rolling cultivator. The garden weasel works the seed further into the soil before dragging. Also, a roller is sometimes employed, which further enhances seed to soil contact though often rolling occurs after the next step, mulching.

Once the seed is worked into the soil, mulch is applied to cover the seed — which aids seed germination, further reduces weed germination, and protects the compost and inoculant as well as provides food for the soil life. The mulch is chopped hay and/or leaves. These materials are run through a bale chopper to make a fine material that spreads easily and does not inhibit germination. The hay is preferably from a late first cutting, which helps avoid some of the seed heads and is a more carbonaceous material. Straw is also occasionally used but needs to be free of grain and both of these materials need to be free of herbicide residue. Leaf is even better as a material as it contains virtually no weed seed, is more carbonaceous, and is most appropriate for feeding the soil. It is much harder to handle in bulk, however, and must be dry for the grinder to chop. Wet, unground leaves have a tendency to mat, which is not conducive to germination. Partially decomposed leaves have been successful on some crops. Those materials should be applied in proper amounts to help cover seed — less for small seeds, more for crops like potato. The mulch does cool the soil which is of benefit during the summer but may slow growth in the cooler months.

Immediately after seeding or planting, the crop is irrigated. This gives the crop a jump on any possible weeds and helps preserve the compost and inoculant. It is possible to irrigate before mulching — significantly more water is needed to saturate and penetrate a dry mulch. But often this is the only irrigation necessary for a crop because of the benefit of no-till on soil water retention. If the crop requires additional fertilizing, liquid nutrient can be applied through irrigation. Specific composts are also used as sidedressing, and foliars are sometimes applied.

This system mostly buries weed seed, and with the layering techniques this control improves every year. Some weeds, however, still slip through and must be dealt with. Since the soil is mulched and crops are broadcast, hoeing is usually not an option. The tool of choice, then, is a serrated weed knife purchased from Johnny’s Selected Seeds, though an aggressive steak knife can also work. They are used to cut annual weeds just below the soil line. For perennial weeds the roots must be removed, so they are either hand pulled or a trowel or similar tool is used for removal. If the weed has gone to seed it is removed from the field. The greatest difficulty for this system seems to lie in the potential for perennial weeds to build up, so attention is paid to removing them. Perennial weeds are generally not as fast growing as annual weeds, so offer less direct competition to a crop. Their strength, however, lies in their tenacity!

Canada thistle, quack grass, and yellow dock are the most prominent weeds presently. In one area quack grass has built to a level that seems to require tillage. As perennial weeds are often intolerant of intense tillage, the tillage equipment stands ready for action if required.

Overall the system has greatly improved the biological activity and diversity of soil organisms. Higher worm populations are obvious, as well as a much improved crumb structure to the soil. Fungal activity is obvious with lots of mycelium present, along with mushrooms. Vastly improved soil water characteristics include the great benefit of proper wicking from lower soil levels, which helps keep the soil life hydrated throughout the seasons, as well as better drainage, water retention, and in-soaking.

Soil air is also enhanced through the ability of the soil to breathe through the crumb structure, while excess oxygenation from tillage is avoided. The soil structure is not pulverized through tillage, and erosion is decreased through mulching and constant vegetative cover. Theoretically there is better nutrient retention and management.

There have been significant decreases in insects and diseases, including: complete lack of brassica flea beetle, absence of root maggot in rutabaga and turnip, no cabbage losses to black rot, and much less leek leaf disease, among many others. Though more effort is required to prepare the beds and make the appropriate compost, overall there is savings because of much less weed control, irrigation, and tillage requirements, as well as way less tractor time. So the iron is largely idle. All of this has led to higher yields of higher quality. The crops are even sweeter and more flavorful, there are very few culls, storage quality is enhanced, and the vibrancy of the crops is noted and appreciated by the customers.




Mycorrhizal Fungi – Powerhouse of the Soil

The soil foodweb of microflora and microfauna constitutes an underground engine of fundamental significance to plant productivity. Mycorrhizal fungi play a key role in the functioning of this foodweb, drawing down plant sugars derived from photosynthesis and providing much needed energy for the soil ecosystem. Mycorrhizal fungi also improve aggregate stability, enhance soil structure, build stable soil carbon, improve plant water use efficiency and increase the efficiency of utilization of important nutrients like phosphorus, sulphur and nitrogen.

Agricultural research tends to focus on conventionally managed crop and pasture lands where loss of diverse perennial groundcover and/or intensive use of agrochemicals, have dramatically reduced the number and diversity of soil flora and fauna, including beneficial microbes such as mycorrhizal fungi. As a result, the potential contribution of soil biology to agricultural productivity has been greatly underestimated.

What are mycorrhizae and how do they work?

Mycorrhizal Fungi

Mycorrhizal hyphae (white) colonizing the roots (yellow) of a pine seedling.

Arbuscular mycorrhizae (AM) are ‘obligate fungal symbionts’, meaning they must form an association with living plants. They acquire their energy in liquid form, as dissolved sugars, siphoned directly from actively growing roots. Mycorrhizal fungi cannot obtain energy in any other way. They have mechanisms enabling them to survive while host plants are dormant but cannot survive if host plants are removed.

Mycorrhizal fungi produce thin, hair-like threads of cytoplasm (hyphae) with a hyphal tip at each end. One tip enters a plant root and the other tip explores the soil matrix. Although the hyphae are small in diameter — usually less than 10 µm (micrometers or microns – a millionth of a meter) — the mycelial network can extend across many hectares.

Mycorrhizal fungi have a fan-shaped architecture, with long runner hyphae branching into networks of narrower and narrower absorbing hyphae. There can be over 100 hyphal tips at the end of each runner. These networks extend from the root system into the bulk soil, well beyond the zone occupied by the roots and root hairs. The absorptive area of mycorrhizal hyphae is approximately 10 times more efficient that that of root hairs and about 100 times more efficient than that of roots.

An amazing symbiotic relationship

Plants colonized by mycorrhizal fungi can grow 10-20% faster than non-colonized plants, even though they are ‘giving away’ up to 40-50% of their photosynthate to support mycorrhizal networks (photosynthate is the soluble carbon the plant fixed from CO2 and sunlight). One of the reasons for this apparent paradox is that plants colonized by mycorrhizae exhibit higher leaf chlorophyll contents and higher rates of photosynthesis than non-colonized plants. This enables them to fix greater quantities of carbon for transfer to fungal hyphae in the soil.

In exchange for soluble carbon from their host, mycorrhizal fungi supply nutrients such as phosphorus, zinc, calcium, boron, copper and organic nitrogen. It’s an amazing symbiotic relationship. Mycorrhizal hyphae have a tubular vacuole system that allows bidirectional flow. That is, sugars from the host plant and nutrients from the soil can move rapidly and simultaneously in opposite directions.

All groups of mycorrhizal fungi require a living host, but there’s more to it than just plants and fungi. A wide range of associative microflora are also involved. For example, colonization of plant roots by mycorrhizae is enhanced by the presence of certain ‘helper’ bacteria. There are also active colonies of bacteria on the hyphal tips, producing enzymes which solubilize otherwise unavailable plant nutrients.

Mycorrhizae and soil carbon

Glomalin, a long-lived glycoprotein (protein containing plant sugar) is a highly stable form of soil carbon that provides a protective coating for the hyphae of mycorrhizal fungi. Networks of fungal hyphae also provide an important first step for the polymerization of plant sugars, ultimately leading to the formation of humus, a high molecular weight gel-like substance that holds four to twenty times its own weight in water. Humic substances significantly improve soil structure, porosity, cation exchange capacity and plant growth.

Both glomalin and humus are of significance to the current debate on soil carbon transience, as these stable soil carbon fractions cannot be lost from soil during droughts or fires.

Marie Spohn from the Universität Oldenburg has identified mycorrhizae (and the glomalin they produce) as the primary soil carbon stabilization mechanism in sandy soils. Previously, soil scientists have considered carbon sequestration potential to be constrained by the soil’s clay content. The new findings are good news for Western Australia farmers, opening the way for much greater levels of carbon increase in agricultural soils than previously thought possible.

Land management impacts

Increasing the amount of stable carbon stored in agricultural soils via mycorrhizal fungi will require a redesign of many current land management techniques. Factors negatively impacting on mycorrhizae include lack of continuous groundcover, single species crops and pastures (monocultures) and application of herbicides, pesticides or fungicides.

Mycorrhizal fungi are also inhibited by the application of large quantities of inorganic nitrogen or water-soluble phosphorus and by the presence of non-mycorrhizal crops (such as canola). Tillage has a less detrimental effect than previously assumed. Recent studies have shown that the use of chemicals is more harmful than moderate soil disturbance. Biology friendly farming practices based on living plant cover throughout the year (e.g. cover cropping or pasture cropping) and the use of biofertilizers, enhance mycorrhizal abundance and diversity and are more beneficial for soil health than chemical farming systems based on intermittently bare soils and minimal soil disturbance.

Due to their low abundance in annual-based or conventionally managed agricultural landscapes, the important role of mycorrhizal fungi in nutrient acquisition, plant-water dynamics and soil building processes has been largely overlooked.

The types of fungi that tend to survive in conventionally managed soils are non-mycorrhizal, that is, they use decaying organic matter such as crop stubbles, dead leaves or dead roots as their energy source rather than being directly connected to living plants. These non-mycorrhizal fungi have relatively small hyphal networks.

Mycorrhizae and water

It is well known that mycorrhizal fungi access and transport nutrients in exchange for the carbon from the host plant. What is less well known is that in seasonally dry, variable, or unpredictable environments (that is, in many regions of the world), mycorrhizal fungi play an extremely important role in plant-water dynamics. The hyphal tips are hydrophilic (both the end in the plant and the end in the soil) enabling both water and nutrients to diffuse from one end to the other along a moisture gradient.

Mycorrhizal fungi can supply moisture to plants in dry environments by exploring micropores not accessible to plant roots. They can also improve hydraulic conductivity by bridging macropores in dry soils of low water-holding capacity (such as sands).

Further, mycorrhizal fungi can increase drought resistance by increasing the number and depth of plant roots.

Perennial grasses and mycorrhizae

Higher densities of mycorrhizal hyphae are found in healthy perennial grasslands than in any other plant community. It has been estimated that the hyphae in the top 10 cm of four square meters (4m2 ) of perennial grassland, if joined end to end, would stretch all the way around the equator of the earth.

Cash crop enterprises could benefit enormously from widely spaced rows or clumps of long-lived perennial grasses and/or mycorrhizal fodder shrubs. As yet we do not know the required critical mass to improve soil ecosystem function, but it might only need to be 5-10% perennial cover. In diverse plant communities, individual plants are connected by mycelial networks called guilds, enabling exchange of nutrients and water. This may help explain why mixed plant communities often perform better than monocultures.

In addition to the resilience conferred by mycorrhizal guilds, the benefit of permanent mycelial networks in terms of aggregate stability, porosity, improved soil water holding capacity, reduced erosivity and enhanced nutrient availability in soils are immense.

Soil benefits in many ways from the presence of living plants year-round, due to reduced erosion, buffered temperatures, enhanced infiltration and markedly improved habitat for soil biota. Significantly, it is the photosynthetic capacity of living plants (rather than the amount of dead plant material added to soil) that is the main driver for soil carbon accumulation.

Management techniques that improve the vigor of groundcover, foster mycorrhizal colonization, increase glomalin production and enhance the humification process, will contribute to long-term carbon storage, improved soil function and markedly increased resilience to climatic variability.




Nitrogen: the double-edged sword

Nitrogen is a component of protein and DNA and, as such, is essential to all living things. Prior to the Industrial Revolution, around 97% of the nitrogen supporting life on earth was fixed biologically. Over the last century, intensification of farming, coupled with a lack of understanding of soil microbial communities, has resulted in reduced biological activity and an increased application of industrially produced forms of nitrogen to agricultural land.

Globally, over $100 billion of nitrogen fertilizers are applied to crops and pastures every year. Between 10 and 40% of the applied N is taken up by plants. The other 60-90% is leached into water, volatilized into the air or immobilized in soil.

Impacts of inorganic nitrogen

The application of high rates of inorganic nitrogen in agricultural systems has had many unintended negative consequences for soil function and environmental health. Data from North America’s longest running field experiment on the impacts of farm production methods on soil quality have revealed that high nitrogen inputs deplete soil carbon, impair soil water-holding capacity – and, ironically, also deplete soil N (Khan et al. 2007, Larson 2007).

Taken together, these factors have been implicated as the underlying cause of widespread reports of yield stagnation around the world (Mulvaney et al. 2009).

The evidence suggests that although nitrogen is essential to plant growth, the application of large amounts of N as inorganic fertilizer is detrimental to soil — and also detrimental to water. The USDA estimates that the cost of removing nitrate from U.S. drinking water is more than $4.8 billion per year, while nitrogen run-off from farmland is the single largest source of nutrient pollution contributing to the massive ‘dead zone’ in the Gulf of Mexico (Ceres 2014).

Fortunately, the news is not all bad. Rates of fertilizer application have decreased in recent years in some developed countries. France, Germany, and the United Kingdom have achieved success in this area, maintaining high yields with forty to fifty percent less fertilizer than used in the 1980s (Krietsch 2014).

Cost-effective nitrogen management is the key to profitable and productive farming. It is also the key to building soil carbon. Stable forms of soil carbon (such as humus) cannot form in the presence of high levels of inorganic nitrogen, due to the inhibition of the microbes essential to sequestration.

Biological nitrogen fixation (BNF)

On a global scale, biological nitrogen fixation accounts for around 65% of the nitrogen used by crops and pastures. There is scope for considerable increase. The supply of nitrogen is inexhaustible, as dinitrogen (N2) comprises almost 80% of the earth’s atmosphere. The key is to transform inert nitrogen gas to a biologically active form.

Much of the nitrogen currently used in agriculture derives from the Haber-Bosch process, developed in the early 1900s. This process catalytically combines atmospheric nitrogen with hydrogen derived from natural gas or coal, to produce ammonia under conditions of high temperature and pressure. The Haber-Bosch process uses non-renewable resources, is energy intensive and expensive.

Fortunately – thanks to some ‘enzymatic magic’ – atmospheric nitrogen can be transformed to ammonia by a wide variety of nitrogen-fixing bacteria and archaea – for free.

Ideally, newly fixed ammonia is rapidly incorporated into organic molecules such as amino acids and humus. These stable molecules are vital to soil fertility and cannot be volatilized or leached from the soil system. Importantly, the stabilization of nitrogen requires a steady supply of carbon – also fixed biologically. We’ll come to that in a moment.

Which microbes are involved?

It is important to recognize that the ability to fix nitrogen is not limited to bacteria associated with legumes. Chlorophyll is part of a protein complex – hence wherever you see green plants – there will also be an association with nitrogen-fixing bacteria or archaea.

Unlike rhizobial bacteria, most nitrogen-fixing microbes are not able to be cultured in the laboratory. This has presented technical challenges to assessing their ecological function. Recent bio-molecular methods for determining the presence of nifH, the gene for nitrogenase reductase, have revealed a dizzying array of free-living and associative nitrogen-fixing bacteria and archaea across a wide range of environments.

Although procedures for quantifying the amount of nitrogen fixed by many of these groups are lacking, what we do know is that the diversity and abundance of nitrogen fixing microbes are much greater where there is living groundcover (particularly plants in the grass family) throughout the year, compared to soils that have been bare fallowed.

In addition to nitrogen-fixing bacteria and archaea, mycorrhizal fungi are also vitally important to the N-fixing process. Although mycorrhizal fungi do not fix nitrogen, they transfer energy, in the form of liquid carbon (Jones 2008) to associative nitrogen fixers. They also transport biologically fixed nitrogen to plants in organic form, for example, as amino acids, including glycine, arginine, chitosan and glutamine (Leake et al. 2004, Whiteside et al. 2009).

The acquisition and transfer of organic nitrogen by mycorrhizal fungi is highly energy efficient. This pathway closes the nitrogen loop, reducing nitrification, denitrification, volatilization and leaching. Additionally, the storage of nitrogen in the organic form prevents soil acidification.

The liquid carbon pathway

Despite its abundance in the atmosphere, nitrogen is frequently the most limiting element for plants. There is a reason for this. Carbon, essential to photosynthesis and soil function, occurs as a trace gas, carbon dioxide, currently comprising 0.04% of the atmosphere. The most efficient way to transform CO2 to stable organic soil complexes (containing both C and N) is via the liquid carbon pathway. The requirement for biologically-fixed nitrogen drives this process.

If plants were able to access nitrogen directly from the atmosphere, their growth would be impeded by the absence of carbon-rich topsoil. We are witnessing an analogous situation in agriculture today. When inorganic nitrogen is provided, the supply of carbon to associative nitrogen fixing microbes is inhibited, resulting in carbon-depleted soils.

Reduced carbon flows impact a vast network of microbial communities, restricting the availability of essential minerals, trace elements, vitamins and hormones required for plant tolerance to environmental stresses such as frost and drought and resistance to insects and disease. Lowered micronutrient densities in plants also translate to reduced nutritional value of food.

Above ground, plant growth often appears ‘normal’, hence the connection to failing soil function may not be immediately obvious. But underneath, our soils are being destroyed.

Ideally, land management practices – and any amendments used in agriculture – should enhance photosynthetic rate and increase the flow of carbon to soil, by supporting plant-associated microbial communities.

figure1photo Jill Clapperton

Fig. 1. Cross section of a plant root showing the thread-like hyphae of mycorrhizal fungi. Mycorrhiza deliver sunlight energy, packaged as liquid carbon, to a vast array of soil microbes involved in plant nutrition and disease suppression. Organic nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, iron and essential trace elements such as zinc, manganese and copper are returned to plant hosts in exchange for carbon. Nutrient transfers are inhibited when high rates of inorganic nitrogen and/or inorganic phosphorus are applied.

Determining brix levels with a refractometer is an easy way to assess the rate at which green leaves are photosynthesizing and hence supporting associative soil microbes. Anything that reduces the photosynthetic capacity of land or the photosynthetic rate of vegetation is NOT sustainable.

How can we utilize our understanding of the liquid carbon pathway to restore natural fertility to agricultural land?

Aggregation is the key

Aggregates are the small ‘lumps’ in soil that provide tilth, porosity and water-holding capacity. Unless soils are actively aggregating, they will not be fixing significant amounts of atmospheric N or sequestering stable forms of carbon. All three functions (aggregation, biological N-fixation and stable C-sequestration) are inter-dependent.

The microbes involved in the formation of soil aggregates require an energy source. This energy initially comes from the sun. In the miracle of photosynthesis, green plants transform light energy, water and carbon dioxide into biochemical energy, which is transferred to soil as liquid carbon via an intricate network of mycorrhizal fungi and associated bacteria.

What do soil aggregates look like?

Fig. 2. The 2 wheat plants on the left were grown with perennial grasses in a Pasture Crop treatment while the wheat plant on the right was grown in adjacent bare soil, amended with 100kg/ha DAP.

Fig. 2. The 2 wheat plants on the left were grown with perennial grasses in a Pasture Crop treatment while the wheat plant on the right was grown in adjacent bare soil, amended with 100kg/ha DAP.

Note the little lumps adhering to the roots of the Pasture Cropped wheat (Fig. 2). These clusters are formed by microbes utilizing liquid carbon from  the roots. Microaggregates, too small to be seen with the naked eye, are bound together by microbial glues and gums and the hyphae of mycorrhizal fungi (also using liquid carbon), to form bigger lumps called macroaggregates, generally 2-5mm in size (around 1/8th of an inch in non-metric terms).

Macroaggregates are essential to soil tilth, structure, aeration, infiltration, water-holding capacity, biological nitrogen fixation and carbon sequestration. In short, it is not possible to maintain healthy soils without them.

Let’s take a look inside a macroaggregate, courtesy of this fabulous illustration (Fig. 3) by Rudy Garcia, State Agronomist with the USDA Natural Resources Conservation Service in New Mexico.
A key feature is that moisture and liquid carbon levels are higher within root-supported aggregates than in the surrounding soil, while the partial pressure of oxygen is lower within root-supported aggregates than in the surrounding soil. These conditions are essential for the functioning of the nitrogenase enzyme utilized for biological nitrogen fixation and also to the formation of humus.

Fig. 3. Diagrammatic representation of a soil macroaggregate. The green vertical line is a fine feeder root and the green horizontal lines are root hairs. The assortment of red and orange particles are microaggregates while the scattered brown shapes represent particulate organic matter. Light colored spheres are sand grains of various sizes, often coated with oxides of iron and aluminum, while the small yellow ellipses are bacterial colonies, including nitrogen-fixing and phosphorus solubilizing species. The fine strands running in multiple directions are the hyphae of mycorrhizal fungi, essential to the enmeshing of the soil particles and the supply of carbon to microbial communities within the aggregate. Depending on soil pH, there will also be precipitated minerals such as iron phosphate or calcium phosphate. The blue background is water held within the aggregate.

Fig. 3. Diagrammatic representation of a soil macroaggregate. The green vertical line is a fine feeder root and the green horizontal lines are root hairs. The assortment of red and orange particles are microaggregates while the scattered brown shapes represent particulate organic matter. Light colored spheres are sand grains of various sizes, often coated with oxides of iron and aluminum, while the small yellow ellipses are bacterial colonies, including nitrogen-fixing and phosphorus solubilizing species. The fine strands running in multiple directions are the hyphae of mycorrhizal fungi, essential to the enmeshing of the soil particles and the supply of carbon to microbial communities within the aggregate. Depending on soil pH, there will also be precipitated minerals such as iron phosphate or calcium phosphate. The blue background is water held within the aggregate.

Within root-supported aggregates, liquid carbon is transferred from fine root hairs to the hyphae of mycorrhizal fungi, thence to highly complex microbial communities. The microbes receiving this carbon – and their metabolites – are instrumental in the transformation of simple sugars to highly stable humic polymers, a portion of which comprises biologically fixed nitrogen and bacterially-solubilized phosphorus. Iron and aluminum, which occur as oxides in the mineral matrix, are important catalysts.

It is now recognized that plant root exudates make a greater contribution to stable forms of soil carbon (that is, to organo-mineral complexes containing organic carbon and organic nitrogen) than does the above-ground biomass (Schmidt et al. 2011)

But here’s the rub. Mycorrhizal colonization is low when large quantities of inorganic N are applied … and mycorrhiza are inactive when plants are absent. Hence biological nitrogen fixation and humification are rare in agricultural systems where heavily N-fertilized crops are rotated with bare fallows. Further, it has been shown that up to 80kgN/ha can be volatilized from bare summer fallows due to denitrification. If green plants are present, this N can be taken up and recycled, preventing irretrievable loss.

When soil is bare there is no photosynthesis and very little biological activity. Bare soils lose carbon and nitrogen, nutrient cycles become dysfunctional, aggregates deteriorate, structure declines and water-holding capacity is reduced. Bare fallows, designed to store moisture and retain nutrients, become self-defeating.

The maintenance of bare fallows – or the use of high rates of inorganic N in crops or pastures –
or worse, both – results in the uncoupling of the nitrogen and carbon cycles that have functioned synergistically for millennia. Photosynthesis is the most important process underpinning life on earth. Non-legume biological nitrogen fixation is the second.

It is important to distinguish between the nitrogen fixed within nodules on the roots of leguminous plants and the nitrogen fixed within aggregates formed in association with the roots of non-legumes. In the latter, the nitrogen can be incorporated into amino acids and humic substances. This is much less likely to occur in stands of pure legume. Legumes are high in minerals and trace elements and form an important part of agricultural systems. However, unless legumes are grown in mixtures with non-legumes, they can deplete soil carbon via the same mechanism as it is depleted by high-analysis fertilizer.

Enhancing the liquid carbon pathway

There is increasing recognition of the fundamental importance of soil microbial communities to plant productivity. Unfortunately, many biological functions are compromised by commonly used agricultural practices.

Redesign of farming practice is not difficult. The first step is recognition of the importance of the year-round presence of green plants and the microbial populations they support.

Redesign has the potential to significantly reduce the impact of many ‘problems’ associated with chemical farming, including loss of soil C, reduced soil N, soil compaction, declining pH, low nutrient availability, herbicide resistance and impaired water-holding capacity.

There are four basic principles for regenerative agriculture, proven to restore soil health and increase levels of organic carbon and nitrogen. From these, landholders can build an integrated land management package that suits their individual property and paddock needs.
1) The first principle is the maintenance of year-round living cover, via perennial pastures on grazed land and/or multi-species cover crops on farmed land. Almost every living thing in and on the soil depends on green plants (or what was once a green plant) for its existence. The more green plants, the more life.

It’s well accepted that groundcover buffers soil temperatures and reduces erosion, but it is perhaps less recognized that actively growing green groundcover also fuels the liquid carbon pathway which in turn supports, among other things, mycorrhizal fungi, associative N-fixing bacteria and phosphorus-solubilizing bacteria – all of which are essential to both crop nutrition and the formation of stable humified carbon.

2) The second principle is to provide support for the microbial bridge, to enhance the flow of carbon from plants to soil. This requires reducing inputs of high analysis N & P fertilizers that inhibit the

Conclusion

Biological nitrogen fixation is the key driver of the nitrogen and carbon cycles in all natural ecosystems, both on land and in water. When managed appropriately, biological nitrogen fixation can also be the major determinant of the productivity of agricultural land.

Many farmers around the world are discovering first-hand how the change from bare fallows to biodiverse year-long green plant cover, coupled with appropriate livestock management and reduced applications of inorganic nitrogen, can restore natural topsoil fertility.

Improving soil function delivers benefits both on-farm and to the wider environment.

For further information, visit www.amazingcarbon.com

Literature cited

Ceres (2014). Water and climate risks facing U.S. corn production. 11 June 2014. http://www.ceres.org/issues/water/agriculture/the-cost-of-corn/the-cost-of-corn

Jones, C.E. (2008). Liquid carbon pathway unrecognized. Australian Farm Journal, July 2008, pp.15-17. www.amazingcarbon.com

Khan, S.A, Mulvaney, R.L, Ellsworth, T.R. and Boast, C.W. (2007). The myth of nitrogen fertilization for soil carbon sequestration. Journal of Environmental Quality 36:1821-1832. doi:10.2134/jeq2007.0099

Krietsch, B (2014). Artificial fertilizer use levels-off as regions reach state of diminishing returns. http://foodtank.com/news/2014/04/fertilizer-use-levels-off-as-regions-reach-state-of-diminishing-returns

Larson, D. L (2007). Study reveals that nitrogen fertilizers deplete soil organic carbon. University of Illinois news, October 29, 2007. http://www.aces.uiuc.edu/news/internal/preview.cfm?NID=4185

Leake, J.R., Johnson, D., Donnelly, D.P., Muckle, G.E., Boddy, L. and Read, D.J. (2004). Networks of power and influence: the role of mycorrhizal mycelium in controlling plant communities and agroecosystem functioning. Canadian Journal of Botany, 82: 1016-1045. doi:10.1139/B04-060

Mulvaney, R.L, Khan S.A. and Ellsworth, T.R. (2009). Synthetic nitrogen fertilizers deplete soil nitrogen: a global dilemma for sustainable cereal production. Journal of Environmental Quality 38: 2295-2314. doi:10.2134/jeq2008.0527

Schmidt, M. W. I., Torn, M. S., Abiven, S., Dittmar, T., Guggenberger, G., Janssens, I. A., Kleber, M., gel-Knabner, I. K., Lehmann, J., Manning, D. A. C., Nannipieri, P., Rasse, D. P.,  Weiner, S. and Trumbore, S. E. (2011). Persistence of soil organic matter as an ecosystem property. Nature, 478: 49-56. doi:10.1038/nature10386

Whiteside, M. D., Treseder, K. K. and Atsatt, P. R. (2009). The brighter side of soils: Quantum dots track organic nitrogen through fungi and plants. Ecology 90:100–108.   doi:10.1890/07-2115.1




Trying to Build Carbon with Beef at Steady Lane Farm

Like many NOFA members, Janet Clark and her husband got into farming in their mature years.

Having grown up on an Illinois farm with a hard driving father, Janet’s husband never wanted to go back to that life again. But he helped her with her dream. Thirteen years ago they bought a 70-acre dairy in Ashfield, Massachusetts to raise beef. For ten years they came out from the Boston area on weekends to build fences, fix buildings (new roofs, a bigger well a new electrical system) and move stock. Three years ago they made the big move out themselves. He runs a small business from a home office, and she runs the farm.

Janet Clark and her herding dog Emma in the barn at Steady Lane Farm. Peering over the hay pile behind Janet is Fred the bull.

Janet Clark and her herding dog Emma in the barn at Steady Lane Farm. Peering over the hay pile behind Janet is Fred the bull.

The farm is in a beautiful spot, right off and visible from scenic state highway Route 112, with a view overlooking the Berkshires. But it has not been idyllic.

“I’m getting arthritic,” Janet admits. “We haven’t been at peak performance. I have a grass-fed beef operation that has integrity, but it breaks even. It supports the farm and the repair of these old buildings, but I’m just beginning to attend to the soil, which is my major driver.”

Clark has put together a strong base of beef genetics, including Hereford, Angus, Belted Galloway, Murray Grey (an Australian breed) and a few Gelbvieh (a Bavarian breed) in a herd of about 50 cattle. At the time of my visit (April) she had 15 breeder cows and one bull, with the rest yearlings and two-year olds, plus calves just being born.

Janet divides them into two herds: one cow/calf herd of mothers and nursing calves, with the bull added in July for a few months to breed the cows back, and the other of growing feeders who will be harvested at 550 to 600 pounds. The feeder herd contains heifers, so the bull never gets in with them. After weaning in December the calves are moved into the feeder herd and the cows are put on a lean diet of first cut hay. The feeders are kept on a higher protein second cut hay in order to gain weight faster.

“The cows are on pasture during the winter,” she says, “but they have two open barn areas with hay where they can come in at will. If there is no wind it can be zero degrees and they will still be out in the sunshine. They just eat more! This time of year we have new-born calves on the ground and the cow/calf herd remain being aggressive feeders throughout the summer.”

The animals graze on pasture until a hard frost comes at the end of October or early November. Then they get hay for 5 to 6 months until the middle or end of April, when they are able to live on pasture again. They get minerals free choice from a mineral block, along with extra selenium spread on the ground around the block.

The Steady Lane Farm boundary is outlined in pink. The major roadway running from top to bottom is Route 112. The blue stream area is vastly exaggerated compared to the actual boundaries of the waterway.

The Steady Lane Farm boundary is outlined in pink. The major roadway running from top to bottom is Route 112. The blue stream area is vastly exaggerated compared to the actual boundaries of the waterway.

Of the farm’s 70 acres, about 60 are open — half in hayfields and half in pasture – with a stream meandering through. The area has a permanent perimeter fence, and is subdivided into 17 paddocks with temporary electrical fencing on plastic posts. The actual paddock size at any point depends on the size of the herd and the lushness of the grass.

Clark has a sketch of her paddocks which she overlays on a map of the farm prepared by the state department of fish and wildlife defining critical habitats.

“These yellow areas are our hay fields,” she explains. “But with the amount of rain we have in the spring we sometimes haven’t been able to take the first cut when it is best for the field. So we often graze them at that time of year. We like the grass to be knee high before it is grazed. A lot is trampled, not eaten. But that is good for the soil life. We move an electric fence line forward every day, giving the cattle access to new grass. They really line up – it’s beautiful to see. I can’t do mob grazing as intensively as I would like, but I’m just now getting more people involved so I can move them more often.

“The biggest paddock,” she continues, “might be 5 to 8 acres, which would be too big in June but in August might be the right size when the cows are hungry and making lots of milk. When the animals are in any paddock bordering the stream they are limited to how much of it they can reach. The stream is classified as a drainage area in our pasture, and as long as cows have had access to it historically, they can continue to graze it now. Sometimes we let them water there, but often we put in a tub and don’t give them access to the stream.”

One of Janet’s biggest goals for the farm is to improve the quality of the forage. That will result in more livestock on the same land, and faster gain for the feeders going to harvest. Both will make the farm more financially viable. But the fields at the north end of the farm are wet.

“The farmers here before us seeded them with reed canarygrass,” she explains. “That forms a dense mat of roots and enables you to get equipment onto the field earlier. It is a good forage, too, if you harvest it quite green and wrap it for haylage. But then you are using a lot of plastic and after being used for haylage plastic is so dirty that even the people who make plastic lumber and buy things like marine wrap won’t touch it. So you have to landfill it. I don’t want to do that!

“But we can’t make round bales of it,” she continues, “because early in the year we have so much rain we don’t get enough time to let them dry. If you wait until it is mature, however, it is like bamboo – it is not edible. So we often end up grazing it in the spring.”

photo by Jack Kittredge A burro lives with Janet’s cow/calf herd to provide coyote protection.

photo by Jack Kittredge
A burro lives with Janet’s cow/calf herd to provide coyote protection.

If she could get more biodiversity in the grasses in that field she feels it would be more productive, with different plants coming into periods of maximum growth at different parts of the season. But she says she needs to learn more about soils and grasses to know what would work best in wet and sometimes anaerobic conditions.

To help her move the cows, which she does every 2 or 3 days if possible, Clark has her loyal dog Emma.

“When I’m moving the cows,” she explains, “I need Emma to be with me and quiet, so when I call to them they come. But it is fine for her to move them out of my way when needed, and manage their movements generally. Emma is good at nudging cattle, rather than driving them.”

There are coyotes around, of course, and for a week or two after birth the calves are vulnerable to them. So Janet keeps a burro with the cow/calf herd for protection. After a few weeks, however, the calves seem to know enough to stay with the herd for safety.

Clark usually harvests two 2-year-olds per month, shipping them to Adams Farm in Athol for slaughter. She sells to River Valley Market and Debra’s Natual Gourmet in West Concord, as well as on the farm through her self-service shop. Ground beef, roasts, stew beef, and specialty cuts are all $7. Sirloin is $10. Rib eye and Tenderloin are $15. Soup bones and organ meats go for $5.

“The market for grass-fed beef is wide open,” she says. “My price point is high, compared to my competitors, but I can sell what I offer. Grass-fed beef doesn’t finish as quickly as grain-fed, however, at 2 years. It finishes at 2 and a half years!

“People who do this a lot,” she continues, “aim at a hanging weight of 600 pounds. If I can hang at 600 I can sell at a little higher price to the discriminating buyer because there is a little bit more fat in the meat. These guys here might weigh 550 now. They will put on a lot of good weight this spring, but they are getting old and I may lose their backbone. If their teeth begin to emerge the inspector will look at that and say: ‘Sorry, this animal is over 30 months and you are not allowed to harvest the spine or the brain because of Mad Cow Disease.’ It doesn’t really matter how old they are. If the teeth have emerged they take the spine and skull out and my quality butcher doesn’t get to get that meat which is close to the bone.”

Janet is focused on doing a better job as a farmer.
“This is a beautiful landscape, a wonderful community, a great place to live,” she asserts. “But this work really has to be able to pay a salary somehow!”

She thinks, however, that she knows what she has to do: “Our forage quality is not what it should be, we need to track the performance of individual cows better, and I need to attend to the market aggressively.”

Emma checks on some of the feeder cattle grazing in April.

Emma checks on some of the feeder cattle grazing in April.

Clark has been talking with a young couple about taking over the cattle operation. They have considerable experience with beef and she believes they will focus more on the things she should be doing. They are talking about introducing some Devon genetics into the herd, for instance. She is still negotiating with them exactly what the lease arrangement will be, but Janet says the idea is that in 5 or 10 years they will be successful enough to buy the farm and half of the two-unit farm house.

She is also considering diversification into value added product like beef jerky or smoked meat, raising turkeys, and grazing other’s animals at the farm during the summer for a fee.

One other product that Janet feels would help both as an additional item to sell and as an amendment to build soil (and thus forage) quality is a high end compost made from cow manure. She is working with Holly Wescott who, before moving to Ashfield, had made a career working with commercial composters in the state of Washington.

Right now the manure and bedding are piled into windrows and aged before being applied to the fields. But the women envision a far more sophisticated system involving careful testing, mixing with biochar, inoculating with fungi, placing into bins in a heated hoop house and composting with red wiggler worms. The resulting product, rich in worm castings and locally-produced biochar, should appeal to high end gardeners and landscapers, as well as helping the fields and forage at Steady Lane Farm after being limed and trampled into the soil.

Janet is particularly excited about using biochar, which she can get from a local sawmill that has purchased equipment to both generate power and make biochar.

“It is a very stable form of carbon,” she points out, “that still has the structure of the wood. It is very hard but has all these tubes in it that become the repositories for these organisms and some of the minerals which can otherwise be washed out of the soil. It persists in the ground for many years – for millennia. It doesn’t volatilize at the surface. The organisms in the soil, of course, can die. But the idea is to keep a thriving environment for them so there is always teeming life there. And the biochar holds moisture! So it has many benefits for the soil.

“It also helps by aerating the compost,” she continues, “keeping air available because of the spaces in the char. You can detect that aeration by the temperature and the smell of the pile. It doesn’t take a lot of biochar to make these effects – maybe 2% to 5%, by volume.

Emma checks on some of the feeder cattle grazing in April.

Emma checks on some of the feeder cattle grazing in April.

“Some farmers here are buying biochar from Canada,” she concludes. “Some people make their own by burning wood and then shutting down the air to it. There are many different mechanisms for making it. There is a reversed bonfire technique with the tinder on the top and the big logs on the bottom. As the tinder catches fire it works down and begins to shut out the oxygen and by the time the coals turn red you douse it with water. That is an open pile. The old way is to dig a pit and burn in that. You can go online to YouTube and see how to build these chambers within chambers that limit the air to the fire and make a cleaner burn so there are few gases given off. That is the kind of design that the one the sawmill has purchased is built around.”

Clark is also very excited by the work of Allan Savory, demonstrating that cattle can play a major role in building soil carbon because they graze, dung, trample, and then move off an area and don’t return for awhile. That time off enables photosynthesis to build up carbon in those soils so they will hold water, cycle nutrients, and enable long-term humification of that carbon. She feels that her operation can be an example of this approach to building soil.

She hasn’t really determined how she is going to measure and document the carbon increases over time.

“Will it be qualitative,” she asks, “or more quantitative? There are whole protocols to do that. And that will be a part of what we are doing here. A group is coming out from Boston in May to try to help us do that. They are more policy oriented, but I’m telling them it has to work for farmers. Unless you have practices that are at the surface very logical for a farmer it isn’t going to happen. That means that you have to have tools that show exactly what you are doing. That is what we are trying to create here. Something that works for any farmer to say: “I want to be sure that my soil is capturing and storing carbon.” That is what carbon smart farming is.




Land Management & Soil Carbon

In this paired site comparison, parent material, slope, aspect, rainfall and farming enterprise are the same. Levels of soil carbon in both paddocks were originally the same.

On the Left Hand Side (LHS) is a 0-50 cm soil profile from a paddock in which groundcover has been actively managed (cropped and grazed) to enhance photosynthetic capacity.

1carbon2On the Right Hand Side (RHS) is a 0-50 cm soil profile from a conventionally managed neighboring paddock (10 meters through the fence) that has been continuously grazed and has a long history of phosphate application.

The carbon levels in the 0-10 cm increment are very similar. This surface carbon results from the decomposition of organic matter (leaves, roots, manure etc), forming short-chain unstable ‘labile’ carbon.

The carbon below 30 cm in the LHS profile has been sequestered via the liquid carbon pathway and rapidly incorporated into the humic (non-labile) soil fraction. Non-labile carbon is highly stable.

On the LHS, 50 centimeters of well-structured, fertile, carbon-rich topsoil have formed as a result of the activation of the ‘sequestration pathway’ through cropping and grazing management practices designed to maximize photosynthetic capacity. Superphosphate has not been applied to the LHS paddock for over thirty years. In the last 10 years the LHS soil has sequestered 168.5 t/ha of CO2. The sequestration rate in the last two years (2008-2010) has been 33 tonnes of CO2 per hectare per year.

Due to increased levels of soil carbon and the accompanying increases in soil fertility, the LHS paddock now carries twice the number of livestock as the RHS paddock.

Levels of both total and available plant nutrients, minerals and trace elements have dramatically improved in the LHS soil, due to solubilization of the mineral fraction by microbes energized by increased levels of liquid carbon. In this positive feedback loop, sequestration enhances mineralization, which in turn enhances humification.

As a result, the rate of polymerization has also increased, resulting in 78% of the newly sequestered carbon being non-labile. The stable, long-chain, high-molecular weight humic substances formed via the plant-microbe sequestration pathway cannot ‘disappear in a drought’. Indeed, the humus now present in the LHS profile was formed against the backdrop of 13 years of below-average rainfall in eastern Australia.

A major cause of soil dysfunction, as illustrated in the RHS soil profile, is the removal of perennial groundcover for cropping and/or a reduction in the photosynthetic capacity of groundcover due to continuous grazing. In the post-war era, a range of chemical fertilizers have been applied to soils in an attempt to mask reduced soil function, but this approach has merely accelerated the process of soil carbon loss, particularly at depth. The net effect of inappropriate management practices has been compromised landscape function, losses of biodiversity, markedly reduced mineral levels in plants and animals and an increase in the incidence of metabolic diseases. This will no longer do.

Australia is not the only country in which subsoils – and hence landscape function – have deteriorated as a result of inappropriate land management and fertilizer practices. In New Zealand, a country blessed with vast tracts of inherently fertile topsoil, carbon losses are occurring at depth under heavily fertilized pastures, due to the inhibition of the sequestration pathway. To date, alternative management practices have been either dismissed or ignored by establishment science in that country.

It is important to note that the rapid improvements to soil fertility and soil function recorded in the LHS soil profile are dependant on the enhanced photosynthetic capacity that accompanies regenerative forms of cropping and grazing management.




Soil Carbon: Some Frequently Asked Questions

Q: Is it fair to say that carbon is the key ingredient that makes the difference between barren, unhealthy soil and fertile, healthy soil?

A: Yes. The glues and gums that hold soil particles together in the form of aggregates (small lumps) are made from carbon. Aggregation is what gives soil its tilth – making it well-structured, porous and friable. Porosity, in turn, improves the infiltration and storage of water. Carbon derived from plants also provides the energy for the soil biota essential to nutrient availability. Plants give to the soil, rather than take from it, as many people believe. The greatest threat to soil health is bare ground. When soil lies in bare fallow for long periods (eg. between crops) – or if it is over-grazed and has bare patches – it will deteriorate. Around 80-90% of plant nutrient acquisition is microbially mediated. If there’s no energy for the microbes (in the form of carbon) there will be very little nutrient – particularly vital trace elements – for plants. These deficiencies are passed along the food chain to animals and people.

Q: When did humans begin to release carbon into the air through disruption of the soil? Can you explain the process of how this happens?

A: As soon as living plant cover is removed, soil begins to deteriorate. Plant litter (mulch) can maintain the condition of the upper layers of soil (topsoil) but cannot maintain the deeper layers (subsoil). There must be active root growth in subsoil in order for it to remain alive and functioning effectively. Grasslands build more soil – and deeper soil – than forests. Due to these deep, carbon-rich soils – and low numbers of trees – grasslands were traditionally the areas first selected for cropping. However, the removal of the actively photosynthesizing year-round groundcover caused immense damage – not only to subsoils – but also to topsoil through wind and water erosion. Fortunately, this damage can be repaired by restoring the flow of liquid carbon via year-round living cover – such as obtained with the use of multi-species cover crops. Best results are seen when cover crops contain at least 20 different varieties of plants and are strategically grazed.

Q: Do you know when scientists first became aware of carbon loss from soil, and of the possible relationship to climate?

A: In ancient times (as far back as the Roman Empire, and possibly before), the word ‘humus’ was used to refer to what we would call ‘soil carbon’ today. Although the actual composition of humus was not known, it was well recognized as the main determinant of soil fertility (soil ‘fatness’ was the general term used for soil health back then). The first explanations of what humus might actually be composed of began appearing in the scientific literature in the 1600s and 1700s. One hundred years previous, Flemish physician Jan van Helmont (1579-1644) discovered that the growth of plants did not reduce the weight of the soil. He was puzzled as to the source of the plant material. If not from the soil, how did plants grow?
Another two hundred years passed before scientists discovered the miracle of photosynthesis (carbon fixing by living plants). Plants are autotrophic, that is, they build themselves from light and CO2. We now understand that this carbon-fixing process – and the translocation of a portion of this fixed carbon to soil microbes in liquid form – is the driver of soil health. It was in the early 1900s that most of the significant research on humus occurred. A lot of the information was discarded, however, with the dawning of the ‘chemical age’ in the 1940s. The destruction to soils (and the deterioration in food quality) caused by synthetic fertilizers was recognized even as early as 1948.
I don’t know when scientists first discovered the relationship between soil carbon and climate change. Professor Rattan Lal was certainly one of the pioneers in this field (Lal, R., Kimble, J.M., Follett, R.F., Cole, C.V., 1998. The Potential of U.S. Croplands to Sequester Carbon and Mitigate the Greenhouse Effect. Ann Arbor Press, Ann Arbor, MI, 128 pp.). I was the first scientist to hold a conference specifically on the subject of the relationship between soil carbon and climate change in the Southern (and possibly also the Northern) Hemisphere.

Q: Do you endorse Allan Savory’s methods? What are other effective methods for restoring carbon to soil?

A: Any method that increases photosynthetic capacity and photosynthetic rate will restore carbon to soil – provided the flow of carbon is not inhibited by chemicals such as synthetic nitrogen, water soluble phosphorus – and of course pesticides and fungicides. Holistic Planned Grazing is an effective way to increase photosynthetic capacity provided the land manager can accurately determine plant recovery and adjust stock movements to match carrying capacity. In farmed lands where livestock may not be an option, multi-species cover cropping is effective – again, provided the inputs of synthetic chemicals are reduced.

Q: What has happened so far in Australia, in terms of individuals and groups taking action, as well as government activity? Is Australia a pioneer in this realm? What is happening in other countries?

A: Any attempt to verify soil as a carbon sink has been blocked by the chemically-funded scientific organizations in Australia. There are countless documents from departments of agriculture and universities which ‘prove’ that it is not possible to increase the level of carbon in agricultural soils. Despite the volume of expert opinion to the contrary, however, I could take you to many farms where soil carbon has been significantly increased.

Q: Can the earth’s soil sequester just the carbon it previously lost, or can it also actually absorb additional carbon from fossil fuel emissions? If the latter, how does that work? Is the soil’s capacity to absorb carbon limitless?

A: The soil’s capacity to sequester carbon is determined by plant root depth and plant photosynthetic rate. We know a lot more about those things now than we did in the past. Photosynthesis accounts for only a tiny fraction of the light energy that comes to earth each day. If we could figure out how to increase photosynthetic potential and channel more of that energy to soil (as liquid carbon), we could turn every farm into a net carbon sink rather than a net carbon source. That would be great for farmers and unbelievably good for the planet!!
Soil building takes place downwards into the soil profile. That is, as soil health is restored, the soil becomes deeper and deeper. We are finding plant roots at incredible depths on carbon-friendly farms, so I certainly believe we can put all the carbon back that has been lost. Whether we can sequester sufficient carbon to mitigate the ongoing emissions of fossil fuel remains to be seen. Biology-friendly farm practices require far less fossil fuel – and also result in fewer emissions – hence the changed land management of itself will reduce the problem to some extent.

Q: Do you see this movement to focus on soil growing? What has surprised you the most in your work on this issue?

A: From what I’ve seen in my travels around the world, the impetus for soil building is coming from farmers, ranchers and their advisors, rather than from government. Change is being driven by the fact that many farmers are no longer making a profit. Once soil carbon stocks have been depleted, no amount of synthetic fertilizer can maintain yield. There is also an increasing desire on the part of many farmers to reconnect with their land. This vital connection has been lost in the industrial farming model. I don’t believe there’s a farmer on the planet who wants to use more chemicals or destroy soil or make people sick. But sadly, that’s what many are being driven to do. It concerns me that there is neither support nor direction from government to help turn this situation around. There are so many good reasons for improving soils. Applying simple techniques to increase the level of soil carbon will make farming infinitely more enjoyable as well as more productive – and vastly improve the quality of our food. If governments provided financial incentive for soil restoration, they would not need to invest anywhere near as much in hospitals.

Q: Is stable soil carbon the same thing as soil organic matter (SOM)? If not, could you elaborate? Is stable soil carbon inorganic? Does SOM contain carbon? Can both help mitigate climate change? Can SOM eventually turn into stable soil carbon?

A: SOM is derived from plant material, animal remains, compost, manure etc. – i.e. stuff you can see. It is made from carbon and other materials and eventually decomposes to become CO2. This is a catabolic (breaking down) process. During decomposition, the presence of SOM in soil has beneficial effects for the soil food-web, the buffering of soil temperatures and in reducing evaporation. However, SOM is very short-lived (days to months). This is what we call ‘labile carbon’. Great stuff – but not what’s needed to remove CO2 from the atmosphere and lock it away for long periods.
Humus, on the other hand, is a high molecular weight carbon polymer, formed by soil microbes within soil aggregates, from sugars channeled to soil via the hyphae of mycorrhizal fungi living in association with actively growing green plants. The formation of humus is an anabolic (building up) process. Humus is an organo-mineral complex requiring carbon, nitrogen, phosphorus, sulphur and several catalysts, including iron and aluminum. The carbon derives directly from photosynthesis, the nitrogen is fixed by a group of free-living nitrogen fixing bacteria called ‘associative diazotrophs’, while the phosphorus is solubilized by bacteria from either calcium phosphate, iron phosphate or aluminum phosphate (depending on soil mineralogy and pH).
The chemical reactions involved in making humus occur inside soil aggregates. The transformations require microbial activity and the microbes require energy – which is produced by the green plants. That’s why humus cannot form to any significant extent when there are no green plants. Once formed, humus is an inseparable part of the soil matrix and can be very long-lived (as in hundreds of years). Hence it fulfils the requirements for safely removing excess CO2 from the atmosphere and storing it in soil. Humus is called non-labile or resistant carbon. You cannot see humus – you can only see what it does.
The main blockage to humus formation in chemical ag is the use of synthetic fertilizers (N and P) which inhibit carbon flow to soil. Even though green plants are often present at high densities in cash crops, they are not forming relationships with mycorrhizal fungi and associative diazotrophs and hence not building soil. This is a huge waste of photosynthetic capacity! Simple changes to fertilizer management alone could improve soil carbon content (and farmers’ bottom lines). Farmers are being encouraged to use products they do not need by companies interested only in profit.




Ruminants and Methane

Wetlands, rivers, oceans, lakes, plants, decaying vegetation (especially in moist environments such as rainforests) – and a wide variety of creatures great and small – from termites to whales, have been producing methane for millions of years. The rumen, for example, evolved as an efficient way of digesting plant material around 90 million years ago.

Ruminants including buffalo, goats, wild sheep, camels, giraffes, reindeer, caribou, antelopes and bison existed in greater numbers prior to the Industrial Revolution than are present today. There would have been an overwhelming accumulation of methane in the atmosphere had not sources and sinks been able to cancel each other over past millennia.

caption: Variations in annual changes in atmospheric methane concentrations from 1983 to 2009. Measurements are in parts per billion per year.

caption: Variations in annual changes in atmospheric methane concentrations from 1983 to 2009.
Measurements are in parts per billion per year.

Although most methane is inactivated by the hydroxyl (OH) free radical in the atmosphere, another source of inactivation is oxidization in biologically active soils. Aerobic soils are net sinks for methane, due to the presence of methanotrophic bacteria, which utilize methane as their sole energy source. Methanotrophs have the opposite function to methanogens, which bind free hydrogen atoms to carbon to reduce acidosis in the rumen. Recent research has found that biologically active soils can oxidize the methane emitted by cattle carried at low stocking rates. The highest methane oxidation rate recorded in soil to date has been 13.7mg/m2/day which, over one hectare, equates to the absorption of the methane produced by approximately one livestock unit (LSU).

In Australia, it has been widely promoted that livestock are a significant contributor to atmospheric methane and that global methane levels are rising. There is no evidence, however, to suggest that methane emissions from ruminant sources are increasing. Indeed, it would seem there has been no clear trend to changes in global methane levels, from any source, over recent decades.

The increase in global methane levels from 1930 to 1970 was due to emissions from the production, transmission and distribution of natural gas. There was a tenfold increase in the use of natural gas through the 1960s and 1970s. The source of many of the natural gas emissions, such as leakages from the Trans-Siberian pipeline, have since been rectified. Measurements over the last 25 years show concentrations of atmospheric methane are merely exhibiting natural variation, with no significant trends in any direction

There is therefore no scientific basis for selectively targeting ruminants for a ‘methane tax’, or worse, interfering with this natural process. Farming in ways that enhance, rather than inhibit, soil biological activity, would improve the capacity of agricultural soil to act as a methane sink, helping balance the greenhouse equation. The issue with today’s industrialized approach to agriculture is that methanotrophic bacteria are chemically sensitive. Their activities are reduced by nitrogenous fertilizers, herbicides, pesticides, acidification and excessive soil disturbance.




The Cisgenic Hybrid Seed Conundrum

It is spring planting time, and most farmers are out planting seeds. The process of developing varieties of plant traits is as old as agriculture and farmers have been selecting seed from plants they like and replanting it for generations. They use open pollinated (OP) seed in this process, which in nature creates new varieties by spreading pollen to flowers randomly. When grown in isolation from cross-pollination with different same species, however, OP methods are designed to produce seed offspring very similar to the original parent population. OP seeds will grow ‘true-to-type’ generation after generation. Heirloom seeds are open-pollinated and have been handed down by seed savers for many years.

But since the industrialization of farming, farmers and gardeners have increasingly handed that seed breeding role over to companies that specialize in the genetics of seeds.

The monk Gregor Mendel was the first to get a scientific understanding of seed genetics a generation before the end of the 19th century. His work was discovered at about the turn of the century and in the 1920s Henry A. Wallace (later Ag. Secretary & Vice President under FDR) perfected the process of hybridizing seed – carefully crossing two different parent varieties and producing a new hybrid variety.

The first step in producing hybrids is to breed inbreds. These plants are crossed with themselves for many generations and they become highly uniform genetically. When two different inbreds are crossed with each other the first generation of hybrid seed produced by the cross (the f1 generation) often exhibits uniformity and special size, taste, earliness, or other desirable traits because of “hybrid vigor” or the tendency of that generation to exhibit the best traits of the parents. If the product of planting f1 seed is replanted for an f2 generation, however, the old parental traits recur and the product is neither uniform nor desirable.

Because many plants are hermaphroditic and have both male and female parts, it is crucial to the process of hybridizing to produce a female parent line that is “male sterile” or does not contain viable male gametes. Then, when crossed with another line, all the viable pollen comes from the second parent line. One common way to create male sterility is to do it through the cytoplasm, the non-nuclear material that fills a cell and is inherited only maternally through the mitochondria or plastid genome. This is termed Cytoplasmic Male Sterility or CMS.

This trait of hybrids to not breed true was quite valuable to seed breeders because farmers could no longer save seed for a new generation, but had to come back to the breeder each year and buy a new supply of this valuable f1 hybrid seed. When Wallace started, virtually no corn seed was hybridized, but by the 1940s, 90% of it was, mostly by Wallace’s own company, making him quite wealthy.

For the last couple of decades, however, since the US Supreme Court allowed the patenting of life forms, the momentum in the US seed market has been held by the biotechnology companies with their genetically engineered, transgenic seeds. Transgenic seeds have DNA from a totally different species spliced into them – say a flounder gene spliced into a strawberry. They could never have existed in nature as they could not have been produced by natural breeding.

But a non-transgenic seed breeding technology has been gaining interest among the biotechnologists. Cisgenic (meaning within the same genetic family) hybrid seeds are produced by means that many consider unnatural and offensive. Should these be treated as GMOs and prohibited in organic agriculture? Opinions differ on this and the question needs to be discussed far more widely within the organic community.

Cisgenic seed cell fusion is a biotechnical process using mutagenesis (the creation of mutations) in which the nucleus is removed from a plant cell and replaced by a mutated nucleus from a different plant within the same botanical family. Chemicals and radiation are used in the process to stimulate the mutations. This creates a hybrid plant containing the mitochondrial and chloroplast DNA from one cell and the nuclear DNA from a different one. Cell fusion can also involve protoplast or somatic fusion – meaning the nuclear DNA from two or more plants from the same family are fused so the resulting seed contains DNA from both.

Hybrid seeds were first developed with induced mutagenesis in the early 20th century to possess disease resistance and features to increase yields. Since the 1950’s cell fusion hybrid techniques have evolved from random treatment with chemical/electrical/radiation stimulation to a site-direct mutagenesis process targeting specific genes with “marker assisted breeding”.

This targeted mutation, known as genome editing, uses tools including complex protein structures called “zinc fingers,” or meganucleases, that can selectively insert or silence genes in crop species and induce errors in DNA repair to stimulate mutations. This shortens development time for crops by years, compared to working with traditional breeding and open pollinated seed.

According to a 11/21/2013 news report by Business Week, industry experts say over the past five years breeding and biotechnology have improved on prior haphazard methods of cell fusion mutagenesis by using molecular markers and sequenced genomes of crops to site direct crossbreeding, making conventional breeding more like genetic engineering. The article quotes Paul Schickler, president of DuPont’s Pioneer seed unit as saying “There is not a black line between biotechnology and non-biotechnology, it’s a continuum.”

Business Week also cites reports from the National Academy of Sciences, representing the consensus of experts in the field, saying that the risk of creating unintended health effects is greater from mutagenesis than any other technique, including genetic modification. Mutagenesis deletes and rearranges hundreds or thousands of genes randomly, spawning mutations that are less precise than GMOs. The academy has warned that regulating genetically modified crops, while giving a pass to mutant products, isn’t scientifically justified.

In addition to the regulatory-free environment they operate in, the magazine suggests mutant crops are also gaining in popularity because they’re cheaper to produce. Monsanto spends anywhere from $150 million to $200 million to launch a single genetically engineered product. Japan, by comparison, invested $69 million from 1959 to 2001 on mutant breeds that yielded $62 billion worth of products over that period, according to data from the United Nations’ Nuclear Techniques in Food and Agriculture program.

“These difficulties in getting a GMO to the market, we don’t have in mutation breeding,” says Pierre Lagoda, who heads up the UN program. That’s spurred even more interest in the mutant varieties, he says. In 2013 alone, Lagoda’s program has received requests to help irradiate a record 31 plant species ranging from sugar beets from Poland to potatoes from Kenya.

BASF, the world’s biggest chemical company, developed its Clearfield wheat and other crops through chemical mutagenesis which alters the crops’ DNA by dousing seeds with chemicals such as ethyl methanesulfonate and sodium azide, according to company filings in Canada, reported Bloomberg News in a 11/13/2013 article.

“This has been a technique used for many decades without issue, without concern,” Jonathan Bryant, a BASF vice president was quoted as saying in the Bloomberg news report.

Overall the debate over whether cell fusion and mutagenesis in seed production are genetic engineering has caused confusion and conflicting answers in the organic community. In organic farming transgenic genetic engineering (GE) is banned, but cisgenic seed created by the cell fusion process is permitted under USDA organic regulations. By international organic certification standards, however, established by The International Federation of Organic Agricultural Movements (IFOAM) cell fusion is classified as genetic engineering.

“Cell-fusion is a controversial topic,” says John Navazio, Senior Scientist with the Organic Seed Alliance and Washington State Univ. Extension Specialist in Organic Seed. “IFOAM would like to ban it from organics completely, as they consider it a form of GM. But many of us in the organic community know that that would seriously compromise the ability of organic farmers to grow commercial crops of several brassica varieties.”

“Several of the large production research seed companies that produce organic seed,” he continues, “are not talking when asked which of their hybrids are produced using cell fusion mediated CMS. By the way, there is also ‘naturally occurring CMS’ which we have used in hybrid carrots, onions, and beets for many years and should not be included in this debate.”

“We do know that Monsanto/Seminis are getting into the ‘organic’ seed line,” says Liana Hoodes, director of the National Organic Coalition and National Organic Action Plan. “Which is precisely why OSA advises caution at this point in demanding that farmers use only organic seed — if the requirement to use absolutely only organic seed were made in stone right now, we would find a narrowing of the organic seed line, and a virtual takeover of the organic seed industry by the big boys. Organic has a long way to go to clarify the definition of GE as an excluded method, and if the USDA doesn’t get working with the true organic seed industry, we will indeed see organic seed production consolidated into the big GE guys (Monsanto/Seminis and more).”

Organic seed companies have taken mixed positions on the use of cisgenic cell fusion seeds in organic production.

“At this time we know of 4 varieties we offer that were developed using these techniques. ‘Gypsy’, ‘Diplomat’, and ‘Imperial’ broccoli and ‘Denali’ cauliflower, said Paul Gallione, technical services technician at Johnny’s Selected Seeds in Maine. “CMS is a USDA NOP (national organic program) approved practice at this time and we at Johnny’s will be in tune to any new developments in that arena.”

High Mowing Organic Seeds, an organic seed company based in Wolcott, Vermont, bans the sale of hybrid seeds produced by cell fusion to manipulate plant DNA.

“We do not support or sell cisgenic CMS cell fusion seeds as we believe the process is the same as GMO”, says Tom Furber, general manager of High Mowing Organic Seeds.

Frank Morton an organic plant breeder/seed grower and founder of Wild Garden Seed in Oregon opposes any use of CMS hybrids in organic production.

“CMS hybrids depend upon patented techniques and patented germplasm,” he says. “The process creates hybrids that produce offspring that have sterile pollen or none at all, and this trait is persistent and irreversible, making the genetics unavailable to anyone besides the patent holder. The patent holders are the GMO industry, so only that industry can make use of this breeding technique. If they aren’t GMOs, they sure have all the sociopathic traits of GMOs.”

Politically, in Europe and the US the debate of whether the process of using cell fusion in seed production is genetic engineering comes down to looking at the issue in a product-oriented or process-oriented perspective.

Klaus-Peter Wilbois is head of the agriculture division at the German office of The Research Institute of Organic Agriculture, FiBL.

“In the private organic farming sector as outlined in the IFOAM standards,” he says, “a process-oriented approach prevails. Therefore the use of genetic engineering lab techniques is not in compliance with principals of organic farming.”

Legally, however, current USDA and EU directives are product-oriented, and if cell fusion is used within the same botanical family it is not GE and those seeds are not judged GMOs.

“For instance,” Wilbois continues, “cell fusion techniques which are used to convey cytoplasmatic male sterility (CMS) in cabbage or chicory crops to produce hybrids are regarded as genetic engineering in the organic sector but would not lead to a GMO in a legal sense, since the crops (Japanese radish as CMS donator) belongs to the same brassica family as cabbages like cauliflower or broccoli. The same is true for sunflower and chicory (both asteraceae).”

Right now, farmers wanting to avoid genetically engineered seed and protect their crop’s organic integrity have no way of knowing if their seeds are cisgenic. If the campaign to ban genetically engineered seeds in organic production, currently being promoted by OCA and organic seed breeders (High Mowing Seeds, Wild Garden Seed, Baker Creek Heirloom Seed Company, Adaptive Seeds, etc), converges with state GMO labeling campaigns, there is going to be a flurry in the open pollinating and natural hybrid seed market. As organic farmers, we need to be ready to offer our thoughts on this to our colleagues, our customers, and our certifiers.

Donald Sutherland and his wife Laura Davis are USDA organic certified farmers in Hopkinton, MA. Donald is a freelance writer and a member of the Northeast Organic Farming Association.