With cellulosic ethanol production on its way to becoming a reality, the effects of stover removal on the landscape have not been fully examined and efficient agricultural management practices for biofuel production systems have not been developed. The current UW recommendations (e.g., UWEX A2809) do not recommend changes to nutrient management plans based on biomass removal (i.e., when corn is grown for silage). Data sets which evaluate the short- or long-term effects of biomass removal on optimum N fertilization rates for continuous corn in Wisconsin do not exist. Long-term field research (30+ years) in Wisconsin has shown that continuous corn rotations maintain and often increase corn yields and NUE over time when N is fertilized at UW recommended rates (Bundy et al., 2011); SOC and soil N supplying capability also have been shown to increase. These results indicate that with proper N fertilization and stover additions to the soil, the capacity of the soil to supply N for crop production can be maintained. An increase in biomass removal may jeopardize the sustainability of these agricultural systems. Future research in this area should focus how stover removal affects optimum N fertilization rates. However, the quantity of studies which evaluate the value of crop residue related to N fertilization rates are lacking.
Soil Science Extension
University of Wisconsin Madison