Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2013
Publication Date: N/A
Technical Abstract: Corn (Zea mays L.) stover has been identified as a primary feedstock for cellulosic bioenergy production in the U.S. Corn/Soybean Belt because of the vast area upon which the crop is grown. Developing sustainable cellulosic ethanol from corn stover residue has also been identified as a high priority by the National Energy Administration of China and Petro China. Developing sustainable, ecosystem friendly corn stover production and management systems is therefore a high priority for both the U.S. and China. A review of soil and crop management strategies being evaluated to develop sustainable corn stover harvest strategies is important for a soil structure conference focused on ecosystem services because soil aggregation is an important indicator of soil health/quality that has been shown to be responsive to long-term stover harvest treatments. Initial results from dry aggregate size distribution studies, using samples collected after six complete corn-soybean [Glycine max (L.) Merr.] rotation cycles near Brookings, SD, showed a significant difference between low and high residue removal treatments. Excessive crop residue harvest caused a breakdown of large soil aggregates into smaller more erodible ones. A similar study for fields near Morris, MN, using samples collected from the 0-5 cm depth, also showed an increase in the fraction of aggregates in the two smallest size classes after four stover removal cycles in a corn-soybean rotation. Finally, baseline water stable macro-aggregation (WSA) (i.e., > 250 µ) measurements for a research site near Ames, IA, using samples collected prior to conducting a 5-year stover harvest study, showed mean values for the 0 to 5- and 5 to 15-cm depth increments of 406 and 436 g kg-1, respectively, after 26 years of continuous corn production or 341 and 382 g kg-1, respectively, after 31 years of a corn-soybean rotation. WSA analyses for samples collected following five years of stover harvest are currently being processed for comparison. This information will benefit those in the U.S., China, and elsewhere around the world striving to balance new energy and bio-product uses for corn stover with traditional demands for its use as animal feed, heating or cooking, and erosion prevention.