Soil Responses to Stover Management in the Northern Corn Belt.

Minnesota at the Northern edge of the Unites States Corn Belt is among the top corn producing states in the Country. National and local interest in using corn stover for energy sparked concerns that over-harvesting biomass wound degrade the highly productive soils in the region. Therefore, a study was established in on-farms in West Central Minnesota to complement on-going research in two fields at the Swan Lake Research Farm (Morris, MN). The long term objective of this research is to provide producers with tools to answer the question “How much biomass can be sustainably harvested from a given field and still maintain soil productivity?” The specific objective that will be addressed is what are near-term soil hydrological (infiltration rate, sorptivity, hydraulic conductivity, and flow-weighted pore-size), and aggregate stability responses to harvesting stover and/or cobs. Soils in the fields included a clay loam soil and sandy loam; with field with conventional tillage and no tillage management included. Dry aggregate size distribution and mean weight diameter indicated that harvesting about 50% or more of the stover produced could rapidly result smaller more readily erodible soil aggregates. Stover harvest impacted soil water entry and transmission, which has important implications for crop production, leaching and drainage. On fields included in this study, suggest that concerns of soil degradation if stover is over-harvested are warranted. Thus, harvest recommendations for sustaining these highly productive soils are needed.