Soil carbon—a blind spot in the debate on carbon
By Emma Hockridge | Grist.org
COP15 looks like it may well be a cop out. The world was disappointed when it became clear Barack Obama would not get climate protection legislation through the U.S. Senate, endangering any meaningful global agreement. But a much earlier cop out came when agriculture failed to make it onto the agenda at all.
There is growing awareness of this sector’s significance. Within the E.U., the food we eat represents nearly a third of the climate footprint of consumers. When it comes to tackling farming’s footprint, all eyes have been on livestock-related methane emissions and nitrous oxide emissions from fertilised fields, or the potential to generate energy from biofuels and the anaerobic digestion of animal wastes. Aspirations are low. The 2020 target for agriculture in the U.K.‘s Low Carbon Transition Plan is a voluntary 6-11 percent greenhouse gas reduction, compared to mandatory 20-40 percent targets in all other sectors of the economy.
One big blind spot remains, both in this country and elsewhere: soil carbon. Soil carbon sequestration, according to the IPCC’s scientific advisors on land use, represents 89 percent of agriculture’s greenhouse gas mitigation potential. Soil carbon losses caused by agriculture account for a tenth of total CO2 emissions attributable to human activity since 1850. However, unlike the carbon released from fossil fuels, the soil carbon store has the potential to be recreated to a substantial degree, if appropriate farming practices are adopted. By this we mean organic farming, with its strong reliance on animal fertilizer and avoidance of oil-based inputs and pesticides. Organic farming would remove large quantities of carbon from the atmosphere every year for the next 20 years at least. If all U.K. farmland was converted to organic farming, at least 3.2 million tonnes of carbon would be taken up by the soil each year—the equivalent of taking nearly one million cars off the road. Action to increase soil carbon levels can therefore contribute substantially to the efforts to rapidly cut GHG emissions and avoid dangerous atmospheric CO2 increases.
Furthermore, raising soil carbon levels can make a vital contribution to climate adaptation, by improving soil structure and quality, reducing the impacts of flooding, droughts, and desertification, thereby also improving global food and water security.
So far, soil carbon is largely being ignored by climate policymakers and analysts in the U.K.. Critics have been too quick to dismiss soil carbon sequestration on the basis that the rates of sequestration tend to diminish 20 years after a switch to improved practices. But it is the next 20 years that will be critical in policy terms for delivering major greenhouse gas reductions. Moreover, carbon sequestration still continues thereafter, albeit at lower rates, for 100 years or more.
Recently, there have been encouraging signs of engagement with the issue at the European level. However, in the U.K., action on soil carbon was deferred in favor of a call for more research. Our report Soil Carbon and Organic Farming is a response to that challenge. The evidence it presents suggests that action to raise soil carbon levels—through more widespread adoption of organic farming practices and grass-based and mixed farming systems—can make a significant and immediate contribution to the greenhouse gas mitigation.
Response by Tim Wightman, President FTCLDF
While reduced tilling is one of the optimal goals of a sustainable farming operation...no-till is a tool not a system of farming.
One has to incorporate the nutrients and applied mineral and soil amendments to activate the soil process to begin the ability to sequester carbon..which my company always called building humas for maximum quality and production.
As a soil consultant we are taught when taking a no-till farm to a more biological approach, organic or not, to pull soil samples from no-till ground at a depth of three inches rather than the normal 6 inches we profile....for the very reason that is where all the nutrients are stuck.
We do not advocate mulboard plowing, or deep twisted shovel chisel plowing but it is imparative that one practices fracture of the ground below 10 inches(yoeman plow) but only work in top 5 inches(howard rotavator or shallow incorporating tool) of the surface in order for the soil system to begin to work completely in a zone of about 16 inches..not just the top two of no-till or the 8 inches of our forefathers.
So if we have a zone of 16 inches of active soil we now sequester well over 400% more carbon than listed above and build humas and raise our potential for nutrient dense crops increased production per acre which reduces the need for tillable acres and the fuel to raise it given the soil is much easier to work and takes less fuel and passes to ready for planting crops.
The report is correct in the varied crop rotation and pasture management, however one thing is missing from the data...if one is to feed an all grass diet..it has to be of complete proteins which can only come from mineralized balanced soil..if grass is made up incomplete protiens it must be buffered by starch usually from grain and dry hay to keep the energy levels up to utilize as much as possible and as quick as possible the incomplete proteins for if not utilized the incomplete proteins turn to urea and begin to reduce the growth/production and utilization of the feed intake which begins a slippery slope of more energy expensed to bring all that buffering capacity to the animal.
The upside to a more balanced pasture and mineralized soil.....more feed efficency and more carbon sequestration and free harvesting by the grazing animal reducing the need for oil to grow that animal.
However if the pattern of building mineralized soil is not followed in its natural progression to sequester carbon or build complete protiens the effect of the effort are reduced to a sum zero given the need to balance the diet of the animal to reduce those GHG and feed the world.
If done propely with the correct understanding of biological farming & animal production practices wether conventional or organic we can provide over and above what this report puts out.
Apply the wrong or emotional principals of no-till and we are no further ahead than we are right now....and simple cost of fuel will be your only tool of change.