Effects of wheat straw length and coverage under different mulching methods on soil erosion on sloping farmland on the Loess Plateau

Purpose To explore the impacts of wheat straw length and coverage on soil infiltration, runoff, and sediment production in sloping farmland under different mulching methods. Materials and methods In this study, an indoor simulated rainfall experiment (90 mm·h −1 ) was used to study the characteristics of runoff and sediment production in sloping farmland under different straw lengths (3 ~ 5, 8 ~ 10, and 13 ~ 15 cm), different mulching amounts (1.5, 2.5, 3.5, and 4.5 t·hm −2 ), and different mulching methods (surface mulching and mixed mulch). Results and discussion In the surface mulching, the average infiltration increased with increasing coverage and decreased with increasing length. In the mixed mulching, with the increase in coverage, the infiltration first increased and then decreased. When the coverage was less than or equal to 3.5 t⋅hm −2 , with increasing length, the infiltration first increased and then decreased. However, when the coverage was 4.5 t⋅hm −2 , with increasing length, the infiltration showed an increasing trend. The change trend of the average infiltration was opposite to the change trend of the cumulative runoff and sediment yield. When coverage and length were the same, the runoff cost of sediment control of the surface mulch was generally higher than that of the mixed mulch. Conclusions In this experiment, when the length was 3–5 cm and the amount was 4.5 t⋅hm −2 , the runoff was the lowest, and the infiltration was the highest under the surface mulch. The sediment production was the lowest when the length was 8–10 cm and the coverage was 3.5 t⋅hm −2 under the mixed mulch. Straw mulching can reduce soil loess, which has certain significance for soil erosion control and the healthy and sustainable development of agriculture.