Use of Manure, Compost, and Cover Crops to Supplant Crop Residue Carbon in Corn Stover Removed Cropping Systems

Abstract

The emerging cellulosic‐based ethanol industry will likely use corn (Zea mays L.) stover as a feedstock source. Growers wishing to maintain, or increase soil C levels for agronomic and environmental benefit will need to use C amendments such as manure, compost, or cover crops, to replace C removed with the corn stover. The objective of this research was to determine the effect of cover crops, manure, and compost on short‐term C sequestration rates and net global warming potential (GWP) in a corn–soybean [Glycine max (L.) Merr.] rotation with complete corn stover removal. Field experiments consisting of a corn–soybean–corn rotation with whole‐plant corn harvest, were conducted near East Lansing, MI over a 3‐yr period beginning in the fall of 2001. Carbon amendments were: compost, manure, and a winter cereal rye (Secale cereale L.) cover crop. Compost and manure amendments raised soil C levels in the 0 to 5 and 0 to 25 cm soil profile but not in the 5 to 25 cm soil profile over the relatively short‐term duration of the study. Total soil organic C (SOC) (kg ha−1) in the 0 to 25 cm profile increased by 41 and 25% for the compost and manure treatments, respectively, and decreased by 3% for the untreated check. Compost and manure soil amendments resulted in a net GWP of −1811 and −1060 g CO2 m−2 yr−1, respectively, compared to 12 g CO2 m−2 yr−1 for untreated.