Temporal variation in soil rill erodibility to concentrated flow detachment under four typical croplands in the Loess Plateau of China

Abstract

Soil rill erodibility (K_r) is an important parameter for process-based soil erosion models since it reflects the soil's ability to resist concentrated flow detachment. Detailed information on the temporal variability of K_r remains scarce but critical to accurately predict rill erosion. This study was conducted to investigate the temporal variations in K_r of a silt loam loess soil using the undisturbed topsoil samples collected from four typical croplands (corn [Zea mays L.], millet [Setaria italic], soybean [Glycine max], and potato [Solanum tuberosum L.]) and to further quantify the potential factors causing those changes in the Loess Plateau of China during one growing season from early April to late September of 2012. The results showed that the measured mean rill erodibility varied greatly with types of cropland. The potato land had the maximum mean K_r, and followed by corn, soybean, and millet. The K_r of the four croplands fluctuated considerably over time and tended to decline with root growth. Temporal variations in K_r were closely related to tillage operations, soil consolidation, water-stable aggregates, and root growth. The rill erodibility could be well predicted with root density, soil cohesion, and initial soil moisture content (NSE ≥ 0.82). Further studies are needed to detect the effects of root diameter of different plant types on rill erodibility.