How does runoff respond as surface residue increases?

As surface residue increases, runoff typically decreases. This is due to the fact that residue, such as crop residue or cover crops, plays a significant role in improving soil structure and increasing water infiltration. The presence of surface residue helps to slow down the flow of water across the surface, allowing more time for it to be absorbed into the soil rather than running off into waterways.

Moreover, residue can intercept rainfall and reduce the erosive energy of raindrops, which can further enhance water absorption. Additionally, as residue decomposes, it contributes organic matter to the soil, improving its overall health and water-holding capacity. Therefore, with more residue on the surface, the likelihood of runoff is significantly reduced, leading to improved moisture retention in the soil and better water quality outcomes.