The Carbon Connection

* Recognize that even annual crop systems can transition away from greenhouse gas emission to carbon sequestration in the form of carbon compounds.

The Institute’s 29-year-long Farming Systems Trial (FST) 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.

Scherr and Sthapit target these agricultural solutions:

“In terms of climate change, landscape and farming systems should actively absorb and store carbon in vegetation and soils, reduce emissions of methane from rice production, livestock, and burning, and reduce nitrous oxide emissions from inorganic fertilizers. At the same time, it is important to increase the resilience of production systems and ecosystem services to climate change.” (p 33)

The Institute’s work shows that organic practices have the power to work toward these solutions. We know, for example, that mycorrhizal fungi—microorganisms that work in symbiosis with plant roots and help supply them with nutrients—are more prevalent in the carbon-rich soils of organically managed systems. Mycorrhizae secrete glomalin, a glue-like substance, that actually conserves organic matter by aggregating it with clay and mineral soil particles. While mycorrhizae have been the focus of our research on soil microbial life over the past few decades (conducted in conjunction with USDA researcher David Douds), they are part of a vast community of organisms found just below the soil surface that deliver diverse but comparable benefits to the crop ecosystem when soil is managed for health and biodiversity.

Minimal tillage, advocated in the report, has many benefits as well, and is most effective when used in concert with a diverse rotation. Reducing tillage also presents an effective way to cycle nutrients and store carbon. As Scherr and Sthapit point out, tillage can disrupt critical microbial functions by exposing anaerobic microbes to oxygen and suffocating aerobic microbes by working them deeper into the soil. Minimal tillage encourages a more biologically rich soil environment than does no-till, with less carbon loss than conventional tillage.

The authors suggest, finally, the use of the FAO Global Carbon Gap Map which helps identify areas where soil carbon storage is greatest and targets geographic regions where it is lacking. This map could pin-point the most promising regions to start using organic methods to restore degraded land.

The individual practices recommended by the authors are already used in various locations throughout the world. These carbon-building techniques, when they are coordinated into a dynamic system, constitute what the Rodale Institute calls regenerative organic agriculture. Scientific examination and practical application of each individual component is vital to understand their roles in a complete organic system. With this understanding, we can then work effectively with farmers to implement as many practices as quickly as possible to affect real carbon sequestration benefits.

Research and outreach provide the practice guidelines that allow food producers to make meaningful changes to their field and rangeland management. Policy makers and consumers are critical, however, in providing the economic support that allows farmers to transform agriculture into a climate-saving force around the world.

See Scherr and Sthapit’s chapter, “Farming and Land Use to Cool the Planet” .

Thanks to communications intern Genevieve Slocum for her research and writing on this post.

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