In a study of South Dakota agricultural practices over the past 25 years, a team of ten scientists at South Dakota State University have documented that modern farming practices measurably increase the yield potential of the soil, and capture carbon in the environment. The result is literally a cleaner, more economically vibrant environment.
The study was the subject of two international publications. It appeared first in volume 104 on pages 763 to 770 of the Agronomy Journal; and more recently in Better Crops with Plant Food, published by the International Plant Nutrition Institute.
This, first-of-its-kind study was based on more than 95,000 soil samples collected from farmer's fields across eastern and central South Dakota between 1985 and 2010, according to Dr. David Clay, SDSU Professor of Plant Science and one of the lead researchers on the project.
The study specifically determined the South Dakota surface carbon sequestration potential and associated partial carbon footprint for corn-based ethanol production. Findings support the theory that many of the surface soils in the region became carbon sinks when seeded with corn.
"The soil organic carbon contents in surface soils have increased 24 percent! These increases directly boost the soil's yield potential, while reducing agricultural impact on the environment," Clay said.
In a direct comparison between yields in 1985 and in 2010, corn yields are 60 percent higher, soybean yields are 19 percent higher, and wheat yields are 53 percent higher. These yield increases have resulted in more than $2 billion in addition corn, soybean and wheat sales.
Over this time period, no-till adoption has also increased. For example, in central South Dakota, no-tillage adoption increased from 5 percent in 1986 to 73 percent in 2009. During the same time, clean tillage decreased from 25 percent in 1985 to 1 percent in 2008.
Another scientist, Dr. Gregg Carlson, SDSU Professor of Plant Science, said the study shows that South Dakota fields used to produce corn, wheat and soybeans become carbon sinks as opposed to carbon dioxide sources. "The carbon stored in South Dakota's 12 million acres of cropped land over this 25 year study period is equal to the carbon emitted from 17.8 billion gallons of gasoline," Carlson said.
Dr. Doug Malo, Distinguished Professor of Soil Science at South Dakota State University, said, "The increase in surface soil organic carbon levels is an excellent example of how the Land Grant mission in collaboration with federal and private industry partners works together to enhance the economic and environmental well-being of the clientele we serve, which are the people of South Dakota."