Corn Residue Removal for Lignocellulose Ethanol Production and Its Potential Impact on Soil Health.

Agriculture management practices can significantly impact soil health biological, chemical, and physical properties through changes in C inputs and C losses. This study investigated the short-term effects of tillage (no-tillage [NT] and chisel plow [CP]), residue removal rate (0, 50, and 100%), and N rates of 0, 170, and 280 kg N ha^-1 on soil C storage, soil bulk density, water infiltration, aggregate stability, and soil compaction. Studies were established in 2008 and continued to 2011 on a Nicollet and Canisteo clay loam (poorly-drained) soil association at Ames, central Iowa site (AC) and a Marshall silty clay loam (well-drained) at Armstrong Research Farm, southwest Iowa site (ASW) in continuous corn (Zea Mays L.). Findings from the C budget show that under CT with an N rate of 170 kg N ha^-1 in continuous corn, there was no significant change in net soil C with no residue removal. Any residue removal had negative impacts on soil bulk density, water infiltration and aggregate stability at both sites regardless of N rate. Increasing N rate from 170 to 280 kg N ha^-1 resulted in greater potential C inputs from above and belowground biomass, although C losses were not significantly different across N rates. Averaged across both tillage systems and at 280 kg ha^-1 N rate for continuous corn, approximately 5.10 and 4.18 Mg ha^-1 and 5.23 and 5.18 Mg ha^–1in 2010 and 2011 for AC and ASW sites, respectively of the residue should remain on the field to sustain soil C. These finding suggest that residue removal needs to be approached on yearly basis with particular consideration to site’s yield potential and weather condition as the residue biomass production can be variable.