Agricultural methods over the past 12,000 years have been responsible for two-thirds of our excess greenhouse gases, essentially mining soil carbon and converting it to carbon dioxide and methane, beginning a slow stable warming that now accelerates with burning of fossil fuel. The unintended consequence has been the flowering of our civilization. Our scientific community has now realized these consequences and developed a more encompassing wisdom.
Modern agriculture has evolved its ability to remove limitations to plant growth, from burning forests for ash fertilizers, to slaughtering bison and fertilizing fields with their bones, to importing guano from remote Pacific islands. In 1913, crafty Germans figured out how to suck nitrogen from the air and now we are able to create natural gas derived fertilizers. These chemical fertilizers have overcome nutrient limits to growth for 100 years.
NPK and the “Green Revolution” in genetics have brought us to where we are today, all made possible by basically mining soil carbon stocks. So we have now hit a carbon limit in two distinct ways. The first is continued loss of soil carbon content, the second is fossil carbon energy cost. Our industrialized farming system spends ten cents of fossil energy delivering one cent of food energy.
We cannot go back, but we can go forward with our newly acquired wisdom. Agriculture allowed our cultural ascent and agriculture can now prevent our environmental descent. Wise land management, conservation agriculture and afforestation can build back our soil carbon.
Biochar, basically solidified humus, a crystalline carbon, sharing many humic functions, allows more shuttling of electrons through the soil food web to build much more resident organic carbon, (living biomass and glomalins), in addition to the carbon in the biochar. Humus last for decades doing it’s work in the soil while Pyrolitic carbon char last centuries to millenniums.
We can re-balance the carbon cycle, and beyond that, biochar systems serve the same healing function for the nitrogen and phosphorous cycles, alleviate toxicity in soils and sediments and as a feed additive, cut the carbon foot print of livestock.
Erich J. Knight of Shenandoah Gardens in McGaheysville, Va., was the Policy & Community Chairman of the 2013 North American Biochar Symposium at UMASS-Amherst.