Soil Organic Matter under Long-Term No-Tillage and Conventional Tillage Corn Production in Kentucky
Soil organic matter improves the agricultural quality of soil and helps mitigate certain environmental problems. It improves the soil’s physical characteristics, plant-water relations, fertility status, and overall productivity. It decreases soil erosion and, in doing so, enhances water quality. No-tillage and other forms of conservation tillage may result in higher soil organic matter contents than conventional moldboard plow tillage under similar soil, climate, and cropping conditions. Crop yields are not only affected by soil organic matter; in turn, they affect soil organic matter content. As crop yields increase, more residue is returned to the soil, increasing soil organic matter content. The Maury soil, however, has a thicker and darker colored surface horizon than is normal for soils formed under forest vegetation, indicating influence from grass vegetation. Plant residues accumulate at the soil surface in no-tillage and are not mechanically mixed throughout the plow layer as they are in the case of conventional tillage.