Crop Residue Removal Effects on Corn Yield and Fertility of a Norfolk Sandy Loam

To meet future demands, alternative energy sources will be needed because long-term energy problems have not been solved. Crop residue may provide a readily available on-farm bioenergy source, but effects of removing residue on soil fertility, water conservation, and crop production need further investigation. A 4-yr field experiment was conducted on a Norfolk sandy loam (Typic Paleudults) to determine the effects of removing crop residues on soil pH, extractable nutrient concentrations, and yield of corn (Zea mays L.). Four stover management treatments evaluated between 1979 and 1982 included conventional tillage with stover incorporated, and conservation tillage with 0, 66, or 90% of the stover removed. Treatments were split and evaluated with and without supplemental irrigation. Extractable nutrient concentrations were evaluated by comparing values obtained from an initial soil sampling with those of samples collected each fall thereafter. Ear leaf analyses were used to monitor treatment effects on plant nutrient status. Annual corn stover yields of 3 to 7 Mg ha⁻¹ provided 5 to 11 × 10⁷ kJ ha⁻¹ of potential bioenergy without reducing winter surface cover below 80%. Harvesting corn residues increased annual N, P, and K removal by 26 to 57, 6 to 14, and 49 to 124 kg ha⁻¹, respectively. Soil extractable and plant nutrient concentrations indicated fertilization rates were adequate to compensate for nutrients removed with crop residues. Annual soil analyses showed that surface-applied lime and fertilizer were rapidly leached through low exchange capacity surface horizons, but accumulated in subsoil horizons even when conservation tillage practices were utilized. Irrigation, tillage, and residue management treatments resulted in few significant differences indicating that in this physiographic region, some crop residues could be utilized for bioenergy production. However, plant nutrients contained in those residues would have to be replaced by increased fertilization.