Horticultural Crop Residues In Organic Production and Nutrient Management

Residue management has been well established as a valuable technology for reducing soil erosion and weed growth, improving water quality and infiltration, contributing plant nutrients and nutrient cycling, retaining soil moisture, and increasing microbial activity and productivity. 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 crops were placed in fiberglass mesh bags either at the surface or 15cm deep in a 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 dried, ground, and analyzed for the rate of decomposition, plant nutrients, and C:N ratios. The sub-surfaced 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 recorded on residues of several crops showed that the rate of decomposition of residues was a function of C:N ratios, season, and the placement in soil.