Comparing impacts of corn residue removal and amelioration practices on soil properties after 3, 6, and 10 years

Information on corn (Zea mays L.) residue removal and organic amendment additions to ameliorate removal effects on soil properties is limited. Thus, we compared impacts of corn residue removal at 59% and organic amendments (winter rye [Secale cereale L.]) cover crop and manure every other year at 24 Mg ha-1 on soil organic carbon (SOC) and physical properties after 10 years under irrigated no-till continuous corn on a silt loam in the western US Corn Belt. We collected soil property data after 10 years and then compared it with earlier results from this experiment (3 and 6 years). Cover crop and manure amendments maintained SOC concentration, but no amelioration practice reduced SOC concentration (-15%) from 3 to 10 years when residues were annually removed in 0- to 5-cm depth. Under residue retention, SOC concentration increased with time with largest increase (+41%) occurring under manure amelioration practice in the 0- to 5-cm depth. Residue removal reduced soil wet aggregate stability by 34%, soil dry aggregate stability by 73%, bulk density by 6%, water content at -33 kPa matric potential by 14%, and plant available water by 17% after 10 years in the 0- to 5-cm soil depth but did not affect infiltration rate. Cover crops increased wet aggregate stability (32%), but manure and cover crops had limited effects on other soil properties. Residue removal increased the susceptibility of the soil to erosion and reduced water retention and SOC after 3 years, but such effects were not fully offset by amendments. Corn residue removal at 59% reduced soil wet and dry aggregate stability and water content at field capacity. Residue removal did not negatively affect soil bulk density, infiltration rate, and saturated hydraulic conductivity. Cover crops partially offset residue removal effects on soil organic carbon and soil wet aggregate stability. Manure partially offsets the negative effects of residue removal on soil organic carbon after 3 and 10 years.