What is the minimum percentage of crop residue that must remain on the soil for conservation tillage according to NRCS guidelines?

The correct answer is based on the NRCS (Natural Resources Conservation Service) guidelines, which define conservation tillage practices. According to these guidelines, a minimum of 30% of crop residue must remain on the soil surface after tillage operations to qualify as conservation tillage. This level of residue cover is essential for several reasons: it helps reduce soil erosion by wind and water, improves soil moisture retention, enhances soil structure, and promotes increased biodiversity in the soil ecosystem. By maintaining this level of residue, the benefits of conservation tillage can be maximized, supporting sustainable agricultural practices while protecting soil health.