Crop Residue Removal Effects on Production Costs and Soil Quality.
Douglas Karlen, USDA-ARS, National Soil Tilth Lab, 2150 Pammel Dr, Ames, IA 50011-4420, Stuart J. Birrell, Dept Ag & Bio-Systems Engineering, Iowa State Univ, Ames, IA 50011, Corey W. Radtke, Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415-2210, and W.W. Wilhelm, USDA-ARS, 120 Keim Hall, Lincoln, NE 68583-0934.
Crop residue has been identified as a near-term source of biomass for renewable fuel, heat, power, chemicals and other bio-materials. Our objective is to examine the potential impacts on the soil resource and nutrient replacement costs for different crop residue management strategies. Preliminary data from studies being conducted for continuous corn (Zea mays L.) and a corn – soybean [Glycine max (L.)] on the Clarion-Nicollet-Webster soil association near Ames, IA will be presented. Three crop residue harvest scenarios – top 50%, bottom 50% and the maximum collectable stover (i.e. ~95% of the above-ground plant biomass) were evaluated. Nutrient removal ranged from 8 to 31 or 13 to 50 kg N ha-1, 0.8 to 2.5 or 0.7 to 3.5 kg P ha-1, and 13 to 37 or 13 to 43 kg K ha-1 for continuous corn or rotated corn, respectively. The nutrient replacement values ranged from 15 to 50 USD ha-1 for the three harvest scenarios under continuous corn and from 18 to 68 USD ha-1 for rotated corn. Ethanol conversion efficiencies, soil quality indicator data and its interpretation with the Soil Management Assessment Framework (SMAF) are also being determined. This study will provide important information regarding the sustainability of harvesting crop residue for bio-fuels or other bio-products.