Corn Residue Particle Size Affects Soil Surface Properties

Abstract

Core Ideas Corn harvesting practices generate characteristic residue particle size distributions. Corn residue particle size influences its composition and decomposition. Residue particle composition and decomposition influence soil properties, i.e., soil C and N. Mechanical harvesting operations affect soil properties via residue size distributions. Field operations may differentially influence crop residue size distributions, altering residue decomposition rates and soil carbon (C) and nitrogen (N) dynamics. In a laboratory microcosm study modeling corn residue distributions observed in a no‐till cropping system, microbial respiration was initially (first 30 d) inversely proportional to residue particle size across four size classes. Subsequently (30–60 d), respiration in the smallest particle size decreased in relation to the larger size classes. Residue particle size significantly increased soil C levels, with the smallest sizes producing the longest‐lasting effects (150 d). Smaller residue size classes initially (30 d) immobilized more soil N compared with larger size classes; however, at 150 d, the smaller size classes had mobilized increasing amounts of N while the larger size classes had progressively immobilized more N. We conclude that crop residue management operations changed characteristic residue size distributions that moderate decomposition activities and result in unique soil C and N dynamics, possibly influencing soil properties, including nutrient availability.