Economics of Residue Harvest: Regional Partnership Evaluation

Economic analyses on the viability of corn (Zea mays, L.) stover harvest for bioenergy production have largely been based on simulation modeling. While some studies have utilized field research data, most field-based analyses have included a limited number of sites and a narrow geographic distribution. An Iowa case study is developed illustrating the use of data extracted from a database of geographically distributed field studies for a region-specific economic analysis. The analysis utilizes grain and residue yield and associated management information from two Iowa field research sites that are Sun Grant Regional Partnership locations associated with the Corn Stover Regional Partnership Team and the Renewable Energy Assessment Project (REAP). This information is used with the Biomass Logistics Model, to quantify costs for delivery of corn stover to a biorefinery for three stover harvest strategies. Results show that economics tends to drive residue harvest toward higher removal rates. However, higher removal rates can degrade soil resources. Limiting harvest quantities to leave sufficient residues to protect against excessive erosion and maintain soil organic carbon levels may provide economic incentives for producers to adopt cropping practices, such as no-till and cover cropping, allowing for higher harvest rates and reducing biomass costs to the biorefinery.