Long-Term Effects of Cover Crops on Crop Yields, Soil Organic Carbon Stocks and Sequestration

A 12-year cover

crops study on the effects on SOC sequestration, storage, retention and loss

and corn and soybean yields was conducted in southern Illinois. The use of

cover crops for the maintenance and restoration of soil organic carbon (SOC)

and soil productivity of previously eroded soils were evaluated. No-till (NT),

chisel plow (CP), and moldboard plow (MP) treatment plots with and without

cover crops were established in 2001. The plot area was on sloping with a

moderately well drained, eroded soil. The average annual corn and soybean

yields were statistically the same for NT, CP, and MP systems with and without

cover crops. By 2012, the cover crop treatments had more SOC stock than that without

cover crops for the same soil layer and tillage treatment. The NT, CP, and MP

treatments all sequestered SOC with cover crops. A pre-treatment SOC stock

baseline for rooting zone was used to validate the finding that cover crops

sequestered SOC in the topsoil, subsoil and root zone of the NT, CP and MP

treatments during the 12-year study. Additional sequestered SOC was lost as a

result of being transported off of the plots and retained in lower slopes,

transported to the stream or released to atmosphere.