RESIDUE MANAGEMENT TO MAXIMIZE CROP PRODUCTION AND ENVIRONMENTAL PERFORMANCE: A SYSTEMS APPROACH

Objective 1: Conduct residue decomposition experimentsto improve our fundamental understanding of crop residuedecomposition. Specifically, we will measure decomposition of individual plant organs(leaves, stems, and cobs/pods). We hypothesize that decomposition rates vary moreacross organs than they do across two very different crop species (i.e., corn and soybean).Objective 2: Develop new residue decomposition equations within the APSIM modelthat operate at the organ level, and thus better predict and explain residue effects on soilplant-atmosphere processes including drainage, fertilizer NUE, grain yield, NO3 leaching, denitrification, and soil N mineralization. We hypothesize that plant organ basedrepresentation of crop residue decomposition dynamics will improve predictive andexplanative power of these processes.Objective 3: Use the improved model to identify residue management strategies that areeconomically sustainable in the near-term and environmentally sustainable in the long term.We hypothesize that the improved model can reduce the risk and uncertaintycurrently associated with the effects of residue harvest on crop production andenvironmental performance.