Impact of Corn Stover Harvest on Crop Productivity, Soil Properties and Erosion.

Corn stover is a potential raw material for ethanol production, but its use must consider impacts to productivity and soil properties. A six-year study was conducted at two locations in Wisconsin with three stover removal rates (0, 50 and 100%) and six N fertilization rates to determine stover harvest impact on productivity and soil properties. A separate study focused on determining differences in erosion rates with stover harvest, and determining if row configuration (seeding rate and spacing) could lower erosion. There were some statistically significant differences in corn grain yield with stover harvest rate, but no clear trend was discernable. Reductions in SOM, and soil test P and K were observed at both locations after three or more years of stover harvest. Soil bulk density increased slightly with stover harvest, possibly because of the additional equipment traffic of the harvest operation. Even though yields were not clearly reduced with stover harvest in the six year study period, a yield reduction might be possible given the trends in soil properties if this practice is continued long-term. Other soil types or marginal soils can be affected to a greater extent, especially at a 100% harvest rate. For example, grain yield declines were observed in two out of three years with stover harvest in the erosion study which was conducted in sloping land. In order to prevent declines in productivity, a more feasible option might be to harvest 50% of the stover for no more than three consecutive years.