Synergies between cover crops and corn stover removal
Abstract
The potential harvest of corn stover as a feedstock for biofuels to meet government mandates has raised concerns about the environmental impacts of its removal from fields. Furthermore, in order to meet these mandates, larger quantities of stover will be required. As a result, increased attention has been placed on sustainable agronomic practices, such as cover crops. While cover crops may offer desirable benefits, adoption comes at a cost. The objective of this study was to determine the extent to which cover crop costs could be compensated by additional stover removal and additional agronomic benefits from the use of cover crops. To meet the objective, we estimated cover crop costs and cover crop agronomic benefits and employ a series of benefit-cost analyses, using stochastic analysis in @RISK. Additionally we tested cover crops with stover removal for 24 Indiana farms in a linear programming model, PC-LP. Cover crop costs ranged from $33.09/acre to $69.81/acre, with variability being driven by differences in the seeding rate and seed cost. Agronomic benefits included reduced erosion, which was calculated using a newly created integrated modeling system. The mean estimated reduced soil erosion with a cover crop and no residue removal was 0.32 tons/acre. A benefit-cost analysis of cover crop agronomic benefits indicated that from a private perspective (on-site) benefits ranged from $37.01/acre to $77.73/acre, and $39.51/acre to $80.24/acre from society's perspective. These benefits were highly influenced by added or scavenged nitrogen (N) from the cover crop; therefore eliminating added N and retesting the on-site case, benefits ranged from $30.24/acre to $54.48/acre. Benefit-cost analyses when considering the agronomic benefits of cover crops resulted in a range of a net loss of $4.49/acre to a net benefit of $35.34/acre for the private perspective, and a net loss of $2.43/acre to a net benefit of $37.85/acre for the societal perspective. Estimating the additional removable stover with a cover crop also utilized the newly created integrated modeling system. Results indicated, that on average, while holding soil erosion constant, an additional 2 tons/acre of stover could be removed. Accounting for cover crop costs and stover removal, a benefit-cost analysis suggested that at a farm-gate stover price of $60/ton, net benefits ranged from a loss of $7.09/acre to a net benefit of $29.63/acre. At a farm-gate stover price of $80/ton, net benefit ranged from $58.53/acre to $95.24/acre. Results from PC-LP indicated that cover crops, along with increased stover removal, impacted crop rotations, increased the total amount of stover harvested, and significantly increased farm profits.
Degree
M.S.
Advisors
Tyner, Purdue University.
Subject Area
Agricultural economics
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