Effects of rainfall intensity on splash erosion and its spatial distribution under maize canopy

摘要

Splash erosion of soil particles by raindrops impacting a soil surface is the initiating mechanism of water erosion. To evaluate the effects of splash erosion on maize, spatial distribution of rainfall intensity and splash erosion rate were measured under maize cover in different growth stages. The relation between splash erosion rate under the maize canopy and rainfall intensity was analyzed. The results indicated that, the average rainfall intensity under the maize canopy gradually increased with the increase in rainfall intensity during the whole growth stage, and splash erosion rate under the maize canopy showed the same change. The average rainfall intensity and splash erosion rate under rainfall of 2.0 mm min(-1) were significantly higher than those of the rainfall of 1.0 mm min(-1). Under the same rainfall intensity, the minimum of splash erosion rate appeared in the jointing stage, while the maximum appeared in the tasseling stage. Compared with the seedling stage, the average splash erosion rates of the jointing stage showed the reduction of 23.9, 24.2, and 41.1 % the corresponding rainfall of 1.0, 1.5 and 2.0 mm min(-1), respectively, under the maize canopy. Under rainfall of 1.0 and 1.5 mm min(-1), there was a significant negative correlation between rainfall intensity under the canopy and splash erosion rate of every spot at the maize tasseling stage. Under rainfall of 2.0 mm min(-1), there was also a significant negative correlation between rainfall intensity and splash erosion rate under the canopy of every spot at maize seedling stage and mature stage. The distribution of splash erosion rate was concentrated at maize seedling stage and mature stage. However, the dispersion degree of splash erosion rate was obvious at jointing stage and tasseling stage of maize. Splash erosion rates showed great difference under the canopy at every period of maize growth. Under rainfall of 1.0 mm min(-1), the high splash erosion rate appeared at two spots, while under rainfall of 1.5 and 2.0 mm min(-1), splash erosion rate was only concentrated in a spot. This study would provide theoretical guidance for soil erosion control based on crop growth and coverage.