Cover Crops and Carbon Sequestration

The recent Climate conference in Paris included talk about cover crops and carbon sequestration. With a buildup of carbon dioxide in the atmosphere, scientists are looking at ways to improve the soil’s capacity to regain some of what it has lost to cultivation and oxidation. Here’s a section of an article from an agronomist at Yale University, speaking about work that Ohio State’s Rattan Lal has done.

According to Rattan Lal, director of Ohio State University’s Carbon Management and Sequestration Center, the world’s cultivated soils have lost between 50 and 70 percent of their original carbon stock, much of which has oxidized upon exposure to air to become CO2. Now, armed with rapidly expanding knowledge about carbon sequestration in soils, researchers are studying how land restoration programs in places like the former North American prairie, the North China Plain, and even the parched interior of Australia might help put carbon back into the soil. 

Dan Towery said that cover crops have lots of promise, bringing carbon back into and storing it in the soil. But, he added that no-till and cover cropping are still new, and gains by one farmer who steadfastly improves the carbon base can quickly be lost again. “All it takes is one tillage trip to lose about 90 percent of what you’ve gained in a decade of cover crops and no-till,” he said. The carbon, even after a decade, isn’t much deeper than two inches. And, there’s no guarantee that, with the sale or rental of that farm, successive farmers will continue to abide with that practice.

So, the idea of paying people to sequester carbon will have to wait some time, he said, until the management practices have settled firmly on the side of conservation tillage.