Removal of agricultural residues for bioenergy and bioproduct use is directly influenced by a number of factors including grain yield, crop rota­tion, field-management practices within a rotation (e. g., tillage), climate, and physical characteristics of the soil such as erodibility and topology.

The goal of the analysis is to develop and apply a methodology to estimate quantities of agricultural crop residues that can be removed for bioenergy and bioproduct use from both continuous crop and multi-crop rotations, while maintaining rain and/or wind erosion rates (Mg/[ha-yr]) at or below the tolerable soil-loss level, T. T is the maximum rate of soil erosion that will not lead to prolonged soil deterioration and/or loss of productivity as defined by the United States Department of Agriculture’s Natural Resource Conservation Service (USDA-NRCS). For the purpose of this article, the methodology developed is applied to the top 10 corn-pro­ducing states (Iowa, Illinois, Indiana, Kansas, Minnesota, Missouri, Nebraska, Ohio, South Dakota, Wisconsin) based on total production (bush­els) between 1997-2001. Three of these states—Kansas, Minnesota, and South Dakota—are among the top 10 wheat-producing states as well.

For each county in the 10 states evaluated, all cropland soil types in land capability classes (LCCs) I-VIII are identified. For each individual soil type, acres of that particular soil type, field topology characteristics (per­centage low and high slopes), erodibility, and tolerable soil-loss limit are obtained from the USDA. These data are used in the rain and wind erosion equations described later. In each of the states analyzed, the following crop rotations are considered (where applicable): continuous corn, corn-soy­bean, corn-winter wheat, corn-spring wheat, continuous winter wheat, winter wheat-soybeans.

For each of these crop rotations, three tillage scenarios (conventional, reduced/mulch, and no-till) are considered. Conventional tillage scenarios consist mainly of moldboard plowing and/or heavy disking, reduced/ mulch tillage scenarios include light disking and chisel plowing, and the no-till scenarios use field operations that provide little or no disturbance to the field surface. Harvest, planting, tillage, and chemical application dates for each field operation are adjusted to reflect the most likely time of year and month that they are expected to occur within each of the 10 states. Tables 2 and 3 describe field operations for each crop rotation and tillage combination analyzed.