Limitations to Residue Harvest in Semi-Arid Cropping Systems: Erosion and Carbon Constraints.

Agricultural residues such as corn stover continue to receive attention as possible lignocellulosic feedstocks for biofuel production. In areas where soil erosion is a major factor in soil degradation, crop residues provide critical protection against the erosive forces of wind and raindrop impact. Further, the need to maintain or build soil organic carbon could further constrain residue collection.

Studies examining the impact of residue removal on erosion and soil organic carbon have given little attention to the semi-arid Great Plains region, even though it is likely that the region will be called upon to play a role in feedstock production because of the extensive production of crops like corn, wheat, and sorghum. Experiments with long duration are important in assessing the potential agricultural impact of residue removal. This study uses the results of a long-term field study of dryland cropping systems in the semi-arid Great Plains to understand the role of crop residues in protecting against soil erosion and the dynamics of soil organic carbon.  The specific objectives were to (i) determine water and wind erosion constraints to collection (ii) examine the influence of residue inputs on carbon dynamics and identify the amount of residue needed to build or maintain soil organic carbon in semi-arid cropping systems. These results are then used to inform the questions regarding potential harvest of crop residues from no-till dryland cropping systems for biomass feedstocks