Caring for the earth

Enhanced soil, healthier food, and better climate

Sometimes the best solutions are hiding right under your feet. The use of a type of charcoal made from plant and animal waste that has been super-heated, in an environment with little or no oxygen, was used thousands of years ago by the Amazonian people to boost fertility of their soils. This man-made soil, very dark and fertile, is found in the Amazon Basin, known by the locals as Terra Preta (black soil).

Terra Preta was rediscovered in 1950 by a Dutch soil scientist, Wim Sombroek, in the Amazon rainforest. Near poor quality soil, Sombroek found man-made Terra Preta, with organic material live after thousands of years. It continues to be used to grow high yields of healthy food, and small quantities are mined.

Within a few years the organic material grows back to restore the layers taken away. Once the organic material is transformed, it stays locked in the ground. Why? Because the organic material is alive. The common name of this man-made charcoal is Biochar. In addition to improving and protecting the soil, it reduces the use of synthetic fertilizers and locks carbon dioxide in the ground. Let’s dig in.

Carbon dioxide sequestration

Forests and vegetation use photosynthesis to capture CO₂. The roots store carbon in the soil. With biochar mixed in the soil, CO₂ is locked in for thousands of years.

Saving the world with small-scale organic farming

Organic fertilizers feed the soil, remain in the soil, and improve it over time. Biochar is a high-performance organic fertilizer. Synthetic fertilizers feed the plants and must be applied repeatedly. The runoff from overuse contaminates rivers and underground water.

Nitrogen from manure used to be a limiting factor in agriculture. In the 1930s, two German chemists found a way to make reactive ammonia, a form of nitrogen that can be applied to the soil and absorbed by plants.

Abundant ammonia was the start of industrial agriculture. Making ammonia is an energy intensive fossil fuel process emitting about 80 million metric tons of CO₂ per year, worldwide. Bulk agriculture using petrochemicals, massive machinery and distribution networks is obsolete.

Synthetic fertilizer is made with reactive nitrogen making it easy for plants to use. As it turns out, reactive nitrogen doesn’t always stay where you put it. Farmers may apply this synthetic fertilizer to their cornfields, but the nitrogen in it will freely spread, mixing with the soil, carbon, oxygen, and water in its environment.

Making and using Biochar

There are many types of soil and many types of biochar. The feedstock is manure and other forms of organic waste, cooked at high temperature without oxygen, a process known as pyrolysis. Unlike combustion, which releases carbon dioxide, pyrolysis allows the organic matter to retain its carbon as it’s transformed into charcoal. Biochar can be spread and mixed in the soil or fed to cattle. Some claim manure-biochar coming from the other end is better for the soil.

Biochar and organic farming benefits

Here are five long-lasting benefits. Reduce the use of fossil fuels and fossil-fuel based fertilizers. Sequester carbon dioxide for thousands of years. Protect our rivers and groundwater from nitrogen overspray runoff. Create alternative distributed energy sources for heat and power. Turn bio-waste into value-added products creating local jobs.

Good jobs for Arkansans

A financial report last week says 40 percent of Americans can’t afford the basic necessities. Local, environmentally friendly jobs, are badly needed. The March 2018 unemployment rate of 3.8 percent is deceptive. The Bureau of Labor Statistics Report shows the number of people not on the labor force increased to 96 million. Why? Because people can’t find a decent paying full-time job.

Biochar and small-scale farming have the potential to improve the soil, provide healthy food and respond to the climate emergency.

For additional details, please google “The ins and outs (and undergrounds) of Biochar,” with Prof. Johannes Lehmann, Cornell University, May 2018. Terra Preta: How the World’s Most Fertile Soil Can Help Reverse Climate Change and Reduce World Hunger, 2016, is an excellent book.

Dr. Luis Contreras