The Real Black Gold: Experimenting with an Ancient Technology in New England

Ancient Amazonians built populous civilizations in rain forests incapable of supporting more than small tribes of hunter-gatherers. How? They applied charcoal as a soil amendment and transformed nutrient poor dirt into rich, dark, fertile soil. Elsewhere in the world, plowing and irrigation drained the soil of nutrients and led to salinization making fertile land barren. We know about the Amazonian people’s farming technology not because they kept records, but because we can still see it in what scientists call Terra Preta, the dark earth created by ancient farmers.

Some of the particles of biochar which Ian used in the plantings

Some of the particles of biochar which Ian used in the plantings

Today biochar – a term coined by Peter Read in 2005 to refer to charcoal applied as a soil amendment – is growing in popularity in the U.S. and elsewhere. This ancient technology is being applied around the world to enhance soil fertility. Farmers in Japan call it “kuntan” or “barazumi,” while Chinese and South Korean farmers refer to it as “fire manure.” Farmers in Sri Lanka have been passing down the technique for generations. The reason we are hearing more about is because it creates an environment in which fungi and bacteria can thrive, leading to increased yields in food production compared to other organic methods.

Ian Back, a recent graduate in Sustainable Food and Farming at the University of Massachusetts-Amherst, aims to demonstrate the advantages of biochar through an experimental fruit forest he planted this year.

Why Biochar?

Back first became hooked on biochar during his junior year when he learned that it could sequester carbon and mitigate climate change. Cooking biomass in a high heat, low oxygen environment, a process called pyrolysis, carbonizes the biomass. Applying the output of the process – the biochar – in topsoil removes the carbon from the atmosphere and locks it into the earth. Johannes Lehmann, a professor in crop and soil sciences at Cornell University, estimates that any one of three approaches to pyrolysis – using forest residues, fast-growing vegetation, or crop residues – could sequester 10% of U.S. fossil fuel emissions.

Because biochar is produced by burning biomass, carbon sequestration may seem counter-intuitive. Indeed, traditional methods of producing charcoal create greenhouse gas emissions and noxious smoke hazardous to those operating the kilns. Modern retorts, however, not only radically reduce smoke and emissions, but create larger amounts of biochar out of the biomass feedstock. And they can have other benefits.

For example Chris Adam designed the “Adam Retort” for farmers in developing countries as an alternative to the inefficient traditional kilns. His design reduces smoke by 75% and produces twice as much biochar out of the biomass feedstock. It can be made relatively inexpensively out of local materials. Vee-Go, a Massachusetts company, uses a catalytic vacuum process to convert agricultural waste into biochar. It does so without releasing any emissions and makes use of waste that would otherwise decompose and produce methane gas, a greenhouse gas which has twenty-five times as much impact on climate change as carbon dioxide. Other systems exist which produce energy or heat from the captured pyrolysis gases.

Back obtained the biochar for the fruit forest experiment from Pioneer Valley biochar producer, Adam Dole. The biochar was produced using the “Adam Retort” design. The retort was constructed by Bob Wells and Peter Hirst, founders of New England Biochar, for about $30,000.

Carbon sequestration and increased food production are not the only benefits of biochar. The material can be an excellent amendment in drought-stricken areas since it acts like a sponge retaining nutrients and moisture for plants to draw upon. Added to animal pastures, it can assist in the breakdown of manures and reduce methane emissions. It can also be used as a feed additive to prevent toxicity or bloat and may even work to reduce radiation. According to Hans-Peter Schmidt, Director of the Dilenat Institute for Ecology and Climate Farming in Switzerland, there are at least fifty uses for biochar from insulation to air decontamination to water treatment in aquaculture, almost all of which are carbon sinks.

The Fruit Forest Experiment

Back’s experiment really started at his home in the summer of 2014. He bought four cubic feet of biochar and made new beds with it in his greenhouse. While he felt his results were good, he yearned for a concrete experiment that would yield not just fruits and vegetables, but hard data. With two fellow students, who initially did not know much about biochar but were game to participate in the experiment, Back entered and won a competition for $1,000 and six cubic yards of biochar from the Pioneer Valley Biochar Initiative. His win put the experiment in motion. Thanks to two UMass professors, John Gerber, Professor of Sustainable Food and Farming, and Stephen Herbert, Professor of Agronomy, he accessed an additional $5,000 for the project. In part because he was graduating in May of 2015 and in part because he wanted the project to become a lasting student enterprise he and his co-conspirators started a student organization which they named Spiritual Ecology and Regenerative Systems Initiative (SERSI). Officially recognized by the UMass Student Government Association, they ensured that the Fruit Forest would be a learning enterprise for future students.

Ian Back adds compost while planting one of the fruit trees in the fruit forest experiment

Ian Back adds compost while planting
one of the fruit trees in the
fruit forest experiment

With the paperwork done and money obtained to finance materials, the physical work began. Back and his team were given a three-quarter acre plot in the UMass Agricultural Learning Center just behind the Pollinator Garden. There they hoped to establish a regenerative ecosystem. In late June they inoculated five cubic yards of biochar in compost tea. Each cubic yard had a gallon of molasses added as well as fertilizer, resulting in three batches of fish and seaweed biochar and two batches of seaweed biochar.

The biochar was disked into two plots where it made up 4% of the top six inches of soil, two plots where it made 3% and one plot where it made 2%. Each plot has a control plot alongside of it so that there are ten distinct plots each of which is 15 feet wide. Plots vary in length from 60 feet to 120 feet, depending on application. The control plots mimic the molasses and fertilizer content of their companion biochar plots so that the role of the biochar can be isolated from the benefits of the other amendments.

Within the Fruit Forest are various plantings, many of which are indigenous to the area. The team planted fruit trees and shrubs, such as cherries, raspberries and sea berries; and perennials, such as buffalo berries, chokeberries, elderberries, and cornelian cherries. Many of the plantings are nitrogen fixing such as the sea berries, Siberian peas, alders, New Jersey tea, and bay berry. Some plantings are pollinator habitats like spicebush and sassafras along with native wildflower mixes and comfrey, all of which are spread throughout the Fruit Forest. The plantings cross over the biochar and control plots. This will enable the students to assess and test the same plants and fruits grown in different plots and to evaluate the health of developing ecosystems.

Students today as well as future students will examine the results over the years. The fruit forest experiment is not just about testing biochar and other amendments, but will be a bountiful place of teaching and learning. Students will assess the health and vibrancy of the plants visually. They will conduct soil tests and analyze the results, comparing results between plots and over time. They will use a refractometer to assess the sugar level of fruits. In two or three years, the students will hopefully see some results of the biochar acting with the soil.

Not just biochar, but regenerative systems

A raspberry plant shortly after planting in the experiment

A raspberry plant shortly after
planting in the experiment

The results will not just be about the benefits (or inadequacy) of biochar. The fruit forest experiment is intended to be a regenerative environment, the results of which will demonstrate the importance of the combination of the fruit forest with biochar. Back argues that the fruit forest is just as important in mitigating climate change as the biochar. It is the balance that is critical: the biochar, the growing perennials and fruit trees, and the untilled, undisturbed soil. The combination gives the biochar the best chance to build organic and microbial life. Like other biochar advocates, Back believes that biochar was not the single factor creating Terra Preta in the Amazon, and it will not be the only element necessary to build regenerative systems today. Biochar used in harmony with other regenerative methods will supply organics, microclimates for microorganisms, microhabitats for small mammals and birds as well as food for humans.

Moving forward, more ancient and traditional agricultural techniques need to be scientifically tested. For example, Back would like to start another multi-plot experiment where he can gather data on the differences between biochar, rockdust and bokashi. Bokashi is another centuries old technique used by Japanese farmers where microorganisms are applied to waste which results in fermentation. Addressing climate change and food security and rebuilding healthy ecosystems will require multiple solutions. Those solutions are more likely to come from organic farmers sharing information than those advocating geo-engineering, genetic modification and other so-called “high tech” solutions.

A row of plantings in the experiment crosses biochar and control plots

A row of plantings in the experiment crosses biochar and control plots

Readers who would like to find out about the results of the Fruit Forest experiment may contact the authors. The SERSI webpages will also post information about the fruit forest experiment in the future at:

Ian Back is a farmer and has a B.S. in
Sustainable Food and Farming

Anita Dancs teaches about food systems at
Western New England University