Stemflow contributions to soil erosion around the stem base under simulated maize-planted and rainfall conditions

Abstract

Stemflow is a primary pathway through which rainwater reaches the ground surface under crop cover. Substantial research suggests that stemflow amounts approach or exceed half the total precipitation on maize cropland; however, few studies have quantified the effect of stemflow on soil erosion during rainfall events. This study aimed to measure the effect of stemflow on soil erosion under controlled situations and determine the effects of stemflow on soil erosion. Maize stems were simulated using a 2-cm diameter PVC tube in 1.3 by 0.25 m steel boxes to introduce stemflows to the soil surface at a 10° slope. The rainfall intensities were 60, 90 and 120 mm/h; the stemflow amounts were 5, 10 and 15 g/s. The results showed that stemflow significantly increased soil erosion. As stemflow increased, the surface runoff and sediment rates sharply increased. Compared with a control slope (no stemflow), stemflow increased the surface runoff and sediment rates by more than three and twelve times, respectively. This result occurred because stemflow contributes to the formation of concentrated flows, which easily trigger rill erosion around the stem base. The sediment rate further increased with rill development. Soil erosion was small if stemflow did not occur during a rainfall event; otherwise, soil erosion was extensive due to stemflow-induced rill erosion. Our results provide new insights for the analysis of crop cover effects and soil erosion on cultivated lands. For maize-planted slopes, stemflow may also be indispensable when determining the soil erosion amount.