Effect of Bioenergy Crop Residue Removal on Secondary and Micronutrients in Minnesota Soils
Study author(s): Deborah Allan, University of Minnesota, Department of Soil, Water, and Climate
Years of study: 2010 – 2011
Location(s): Rosemount MN, Lamberton MN, Northfield, MN
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The amount of secondary and micronutrient plant removal was similar between tillage systems, except at Rosemount where greater Ca, Mg, S and B were removed under CT than ST systems, because of the higher yields and therefore greater biomass removal under CT systems. In addition, the amount of secondary nutrient and micronutrient removal was significantly greater in the 100% than 50% residue removal rate. Despite the higher rate of nutrient removal under 100% treatments, there were almost no changes observed in soil availability of secondary and micronutrients by 2-3 years after establishment of the treatments.
During this same time period, soil quality indicators reflected differences between tillage treatments due to stratification under strip-till systems compared with conventional-till systems, but no differences were detected due to residue removal rates, except in Northfield where POMC tended to be greater in the 0 and 50% than in the 100% residue removal rate. It appears that longer time periods are required to detect effects of residue removal on soil properties, including availability of secondary and micronutrients and amounts of active C and N in these soils.