Combined influences of wheat-seedling cover and antecedent soil moisture on sheet erosion in small-flumes

• Various wheat-seedling cover and soil water content were produced by different applied water.
• Antecedent soil moisture was the predominant factor affecting soil erosion at mini-flume.
• Combined effect of vegetation and antecedent soil moisture on soil erosion was significant.

Assessing and predicting soil erosion requires knowledge of the influences of antecedent soil moisture and vegetation cover as well as of their combined effects on soil erosion processes. Past research typically focused on either vegetation cover or antecedent soil moisture. Even though these parameters are likely related under field conditions, studies on their synchronous combined effect on soil erosion processes are scarce. We conducted laboratory experiments on soil erosion using simulated rainstorms (intensity 77 ± 4.5 mm h−1; 60 min duration) on a light loamy soil under different levels of wheat-seedling cover and antecedent soil moisture that were both produced by different sprayed applications of water (30, 40, 50, 60 or 70 mm) during a 40- to 44-day growing period. The objective was to explore the effect of the combined effects of wheat-seedling cover and antecedent soil moisture on soil erosion. Wheat-seedling cover and antecedent soil moisture increased with applied water levels from 9.7% to 37.2% and from 8.4% to 12.2%, respectively. The shortest time to runoff was observed for intermediate values of cover and antecedent moisture (60-mm water level). Infiltration rates and total infiltration generally decreased with increases in water applications. Runoff rate and soil loss were not significantly different (P > 0.05) among the 40-, 50- and 60-mm water treatments, but abruptly increased under the 70-mm treatment. At the 70-mm level, the total runoff volume and total soil loss were, respectively, between 15% and 37% and between 15% and 45% higher than those at the other water levels were. Antecedent soil moisture was the predominant factor affecting infiltration, runoff and soil loss during the rainstorms. In this study, the effects of the relatively low wheat-seedling covers were obscured by those of the antecedent soil moisture at the small-flume scale. This suggests that the effects of vegetation cover and antecedent soil moisture on soil erosion should be considered together when assessing and predicting soil erosion.