by a siegel
Sat Oct 18th, 2008 at 04:48:48 AM EST
A few days ago, "Can Organics Save Us from Global Warming?" excitedly brought news of a new study from the Rodale Institute entitled Regenerative Organic Farming: A Solution to Global Warming. After now having taken the time to read this report, it seems worth seconding the excitement ... even if perhaps seeking to dampen it a little bit.
The report lays out a sensible explanation a path toward a far more climate friendly, a much more profitable, and somewhat more productive agriculture system. There long-term research provides quite real and substantive information about productivity implications in the fields; the financial benefits for going 'organic'; the potential large scale benefits; and core challenges to achieving greater results.
Perhaps the greatest challenge arena: knowledge and education:
Rodale Institute's experience in training thousands of farms from around the world has proven that the shift to regenerative farming practices is both doable and practical. It's the decision to change that's hard.
Promoted with an edit by afew
These words could fit for almost every arena of the challenge for moving toward an Energy Smart future, as the obstacles are almost always not the real, 'number-crunching' implications but creating the pressure and momentum for change to more efficient energy technologies and practices.
Government farm policy must be transformed in a way that incentivizes farms and drives behavioral change toward wide-scale adoption of regenerative farming practices. Success requires a sustained, multi-faceted national public education campaign, training for farmers in regenerative agricultural methods and legislative action.
Again, all too familiar a set of challenges.
Now, to be clear, this does not look to provide "a solution" (not a Silver Bullet) but Rodale's work seems to provide a clear statement as to something that could be "part of the solution path" (e.g., a Silver BB) toward Global Warming and other challenges before us.
The problem, however, is that there is competing work and competing analysis. Being reminded of this, as quoted by Joe Romm, “Tillage and soil carbon sequestration–What do we really know?” (pdf)
In essentially all cases where conservation tillage was found to sequester C[arbon], soils were only sampled to a depth of 30 cm or less, even though crop roots often extend much deeper. In the few studies where sampling extended deeper than 30 cm, conservation tillage has shown no consistent accrual of SOC [soil organic carbon], instead showing a difference in the distribution of SOC, with higher concentrations near the surface in conservation tillage and higher concentrations in deeper layers under conventional tillage.… Long-term, continuous gas exchange measurements have also been unable to detect C gain due to reduced tillage. Though there are other good reasons to use conservation tillage, evidence that it promotes C sequestration is not compelling.
Okay, so it is clear that organic / conservation tillage makes sense for many reasons, there is uncertainty (however) as to whether carbon sequestration benefits are part of this.
From the report
The Rodale report is worth the read. It makes (and supports) a claim that "practical organic agriculture, if practiced on the planet's 3.5 billion tillable acres, could sequester nearly 40 percent of current CO2 emissions."
Some interesting data/points from the report:
- Some Midwestern soils that in the 1950s were composed of up to 20 percent carbon are now between 1- and 2-percent carbon. This carbon loss contributes to: soil erosion, by degrading soil structure; increasing vulnerability to drought, by greatly reducing the level of water-holding carbon in the soil; and the loss of soil's native nutrient value.
- U.S. food system contributes nearly 20 percent of the nation's carbon dioxide emissions. On a global scale, ... agricultural land use contributes 12 per cent of global greenhouse gas emissions
- On a global scale, soils hold more than twice as much carbon (an estimated 1.74 trillion U.S. tons) as does terrestrial vegetation (672 billion U.S. tons).
- Our studies of organic systems have shown an increase of almost 30 percent in- soil carbon over 27 years. [NOTE: A question, therefore, is how long it would take before a switch to organic systems would sequester the 40 percent that Rodale is asserting?]
- 33-percent reduction in fossil-fuel use for organic corn/soybean farming systems that use cover crops or compost instead of chemical fertilizer ... Rodale Institute's organic rotational no-till system can reduce the fossil fuel needed to produce each no-till crop in the rotation by up to 75 percent compared to standard-tilled organic crops.
- yields from the organic systems matched the yields from conventional systems, except in drought years, when regenerative systems yielded about 30 per cent more corn than the petroleum-based system.
- certified-organic crop prices ranging from 40 to 150 percent higher than standard crop prices
- During the 1990s, results from the Compost Utilization Trial (CUT) at Rodale Institute--a 10-year study comparing the use of composts, manures and synthetic chemical fertilizer--show that the use of composted manure with crop rotations in organic systems can result in carbon sequestration of up to 2,000 lbs/ac/year. By contrast, fields under standard tillage relying on chemical fertilizers lost almost 300 pounds of carbon per acre per year. Storing--or sequestering--up to 2,000 lbs/ac/year of carbon means that more than 7,000 pounds of carbon dioxide are taken from the air and trapped in that field soil.
- In 2006, U.S. carbon dioxide emissions from fossil fuel combustion were estimated at nearly 6.5 billion tons. If 7000 lb/CO2/ac/year sequestration rate was achieved on all 434 million acres of cropland in the United States, nearly 1.6 billion tons of carbon dioxide would be sequestered per year, mitigating close to one quarter of the country's total fossil fuel emissions.
- emissions-cutting equivalent of taking one car off the road for every two acres under organic regenerative agricultural management, based on a vehicle average of 15,000 miles per year at 23 mpg.