Soil splash detachment and its spatial distribution under corn and soybean cover

• Splash detachment rate under crop canopy decreased as crop LAI and rainfall intensity increased.
• Large raindrops formed at the leaves' tips and edges generate drastic erosion.
• The splash from large raindrops was the main portion of splash erosion under the canopy.

To evaluate the effects of splash erosion on crops, throughfall and splash detachment were measured in different crop-growth stages and rainfall intensities under corn and soybean cover. The relation between splash detachment under the crop canopy and leaf area index and throughfall intensity was analyzed. The characteristics of the spatial distribution of splash detachment under the crop canopy were discussed as well. The results indicated that, compared with bare soil, the average splash detachment rate under the canopy during corn growth was reduced from 77% to 43%, with an average of 68% approximately, while a soybean canopy can reduce the splash detachment rate from 77% to 48% with an average of 61% approximately during the growth stage. The splash erosion detachment rate increased significantly with increasing leaf area index and rainfall intensity. The throughfall was concentrated in the centers of rows as crop grows, and a sharp increase in the splash detachment rate was caused by concentrations of throughfall under the canopy, which resulted in uneven distribution of splash detachment. The spatial distributions of splash detachment depended on the spatial distributions of throughfall under the crop canopy. The change in throughfall intensity under the canopy was the main reason for the variation in splash detachment. The reduction of kinetic energy because of interception by the crop canopy contributed to a decrease in splash erosion. However, large raindrops formed at the tips and edges of leaves can generate substantial erosion, and this part of the splash may become the main portion of splash erosion under the canopy. These results indicated that continuous and concentrated raindrops impacted splash detachment and caused its uneven distribution under crop cover.