Decomposition Rate of Sweet Corn Residue in a Heavy Soil as Affected by Placement and C:N Ratio.

Residue management has been well established as a valuable technology for reducing soil erosion and improving water quality. Plant residues contribute nutrients to the succeeding crop and influence soil structure, water retention and infiltration, nutrient cycling, and microbial activities. The rate of residue decomposition in various crop seasons is an integral part of a scientific nutrient management program. As a part of the research being conducted on horticultural crops for nutrient management and conservation planning, fresh residues of sweet corn (Zea mays var. merit) were placed in fiberglass mesh bags either at the surface or 15 cm deep in Memphis silt loam soil (Typic Hapludalf, silty, mixed, thermic) and were allowed to undergo decomposition for a period of six months. Decomposing samples were collected from the field every ten days and analyzed for the rate of decomposition and C:N ratios. The subsurfaced root and shoot residues decomposed faster than the surfaced residues. The decomposition rates of both root and shoot residues were negatively correlated with the low C:N ratios. The results showed that the decomposition of crop residues was a function of C:N ratios and the placement in soil.