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Paul's Research Perspectives By Paul Hepperly |
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Posted January 12, 2006: According to the humorist Will Rogers during the heart of the great depression and dust bowl “We keep makin’ people but we ain’t makin’ any new dirt!” In the intervening 70 years we’ve gained more people and lost more “dirt,” despite improvement in soil conservation. Now comes word that we may be on the verge of finally being able to do what Rogers thought was impossible. The overall arithmetic of soil creation is a balance between all losses by erosion and nature’s painstakingly slow soil creation process. Because agricultural erosion – through overuse and undernourishment -- has mostly overwhelmed nature’s soil production, the net result has been the shrinking of our global soil resource base and a degradation of our natural resources. If we are to prosper in the foreseeable future, we need to cut the losses and accelerate the gains. Stop the bleeding, build the soil As we’ve known all along, organic matter is the glue that holds soil in place so it doesn’t wash or blow away. Once virgin woods or prairie is opened it will lose about 1 percent of its original organic matter per year, soil scientists say. After 50 to 75 years it will stabilize in a new depleted level. Once organic matter is mined out of the soil, fertilizer can supply nutrients but not the water and air-holding capacity crucial for productive agriculture. To halt its loss, soil needs to be covered. Research here at The Rodale Institute® shows that properly managed cover crops (legumes, grains, grasses or mixtures) can reverse soil organic matter loss and actually build new soil organic matter (SOM) – dark and rich. Soil-building crop rotations also reduce atmospheric greenhouse gas emissions, giving agriculture a role in combating the growing impacts of global climate change by putting the black back. The Rodale Institute Farming Systems Trial® (FST), a long-term study comparing different farming systems, shows that we can gain about 1,000 pounds of carbon per acre per year with cover cropping and crop rotation under organic management. This is about twice the sustained carbon gain from standard no-till planting for corn or soybeans. FST shows insignificant amounts of carbon are deposited in our conventional tillage corn and soybean rotations with chemical fertilizer and pesticide inputs. And there are even better ways to enhance SOM, such as our biological no-till system which combines reduced tillage with intensive cover crops and rotation. Looking to our ancestors for the future Back in April I wrote a column titled Carbon is the key. I described the ability of nutrient poor, red tropical soils to be transformed into productive black earth. This apparently took place by hand labor on a large scale more than 1,000 years ago on in an area the size of modern France in the Amazon Basin. The productive persistence of this black from poor red soil has been traced to the addition of charcoal. Much of the work on improving our soil has focused on increased
plant production. If, We are trying to improve our composting process so carbon can be retained more effectively in soil. The Amazon black soils show what’s possible. Whereas many plant residues persist in the soil for months or days and compost can last for years, charcoal‘s soil lifetime has been measured in many centuries. Freeing hydrogen from biomass The largest man-made contributor of carbon dioxide in the atmosphere is the burning of oil, gas and coal from subsurface deposits. An attractive alternative is using plant resources to harvest hydrogen which, when burned, produces water -- not carbon dioxide. Increasing interest is being expressed in a hydrogen economy which will be based on renewable energy resources. In a combustion process called pyrolysis, which excludes oxygen, hydrogen in plant materials can be harvested as a source of energy while conserving carbon and other nutrients as char. If this biomass-based system can reach sufficient scale and scope, farms and farmers can be our next energy providers while gaining the materials which will regenerate the soil while growing more crops. Recent research1 shows the process produced three times the hydrogen it consumes, making it a net energy producer. Further it yielded a nitrogen-enriched char-type fertilizer. This material is highly resistant to microbiological decomposition while also acting as a biological stimulant by providing the “house” for microbial life. To learn more on the agricultural and energy aspects of this process, check out the web site of Epridra, Inc., (www.eprida.com) which describes itself as “a technology development company and social purpose enterprise.” Check out The Epridra Cycle to run an animation showing the biomass to fertilizer, sequestered carbon and energy loop. Regeneration raises the bar Robert Rodale urged us to stay curious, observant and determined to develop systems based on nature’s principles. His goal was to find ways to approach the idea of regeneration, that is, to improve the capacity of the very systems we are using. When we regenerate we use resources intensely yet benefit them as a result. Increasing global and sector competition for dwindling fossil fuels is producing anxiety, higher prices and innovation. As farmers and citizens faced with where to invest our support for new energy sources, why not look for options that have the potential to also renew and regenerate our soils, water, and air. We need to set regeneration as our goal and accept nothing less.
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