ABSTRACT
The “steady-state” level of soil organic matter (SOM) is determined by numerous soil properties which are influenced by cropping practices such as residue management, crop rotation, and many others. Maintaining, or even increasing, SOM at the highest levels attainable under economic crop production requires reduced tillage systems and crop rotations that maximize the amount of residue produced and returned to the soil surface. Sustaining or increasing soil productivity may depend on soil and crop management practices which maintain or increase SOM. Soils were sampled from conventional and no-tillage treatments applied to continuous sorghum, continuous soybean, and sorghum-soybean rotations. Crop management systems that include rotations with high-residue-producing crops and maintenance of surface residue cover with reduced or no-tillage result in greater soil organic carbon and nitrogen, which may improve soil productivity.
