Carbon sequestration in natural systems

Following on the heels of yesterdays posts on rainforests, one the most potent carbon sequestering ecosystems on the planet, today I'd like to discuss the carbon sequestering potential of organic agriculture.

As reported over at Organic Consumers Association, recent reports by Rodale Institute and Worldwatch Institute indicate that if the world were to switch to organic agriculture on it's 3.5 billion tillable acres that land would sequester 40% of our current carbon emissions. Of course it would also drastically reduce the emissions from the production and application of natural gas based nitrogen fertilizers and petrochemical pesticides and herbicides. Added benefits would include reduction of dead zones in coastal ocean zones due to nitrogen runoff, increased biodiversity due to elimination of the application of poisons to the biosphere, not to mention the benefits to human health of removing those poisons from the food chain and drinking water.

The reports recommend;

" multiple strategies for carbon sequestration, including organic farming, reduced tillage, use of biochar to aid in revegetation of degraded soils, retaining forests and grasslands as carbon sinks, agroforestry and perennial cropping to retain more biomass, rotational grazing, and biogas digestion to convert manure into energy and organic fertilizer. They include several good suggestions in ramping up the quest for better perennials, such as looking at more tree crops for food production and finding suitable perennial biodiesel crops."

Rodale instutute has been running a 29-year-long Farming Systems Trial that;

" has shown that, after the initial transition phase, organic annual systems produce a competitive yield and often do better than conventional systems in drought years. This may be due to a relatively high rate of moisture-absorbent carbon content in organic rotations, as Institute trials also show accumulation of 500 lb/C/a/yr (legume) to 2,000 lb/C/a/yr (compost) in various long-term observations."

The OCA recommends;

• "Rethink the value of soil carbon, elevating it to the position it deserves. This means reprioritizing our land use patterns, moving preservation of prime farmland to a high priority for national ecological security.
• Focus on building biologically active soil organic matter that leads, by default, to more sustainable and environmentally sound agriculture.
• Credit the added benefits of fertilizer reduction and water management. Since organic systems can use compost, manure and cover crops for fertility, they gradually eliminate the need for chemical fertilizers due to increases in naturally cycling fertility. At the same time, the soil water-holding capacity improves to better maintain crop growth and production in drier and wetter years. Keeping diverse and nearly year-round vegetative cover growing on the soil surface has the benefit of holding soil in the field (rather than losing it to erosion) and improving rainwater infiltration through the soil profile to recharge groundwater.
• Recognize that even annual crop systems can transition away from greenhouse gas emission to carbon sequestration in the form of carbon compounds."

Meanwhile the climate bill in the US exempts the carbon impacts of industrial agriculture at the same time we are pouring billions into the fantasy of carbon sequestration at dirty coal power plants.