RELEASE OF NITROGEN FROM CRIMSON CLOVER RESIDUE UNDER 2 TILLAGE SYSTEMS

The N contained in winter cover crops (particularly legumes) is a potentially important source of N for succeeding crops. The purpose of this study was to determine N release from crimson clover (Trifolium incarnatum L. ) residue under no-tillage and conventional tillage conditions. Residues contained in nylon mesh (53 mu m) bags placed either on the surface of no-tillage plots or buried at plow-layer depth in conventional tillage plots were removed for dry matter, C, and N determinations at 1, 2, 4, 8, and 16 weeks after placement in mid-May. The rate of N disapperance was more rapid under conventional than no-tillage conditions. Under humid, subtropical conditions, release of N from both surface and buried residue from winter legumes, is sufficiently rapid to be of significant benefit to the summer crop.