降雨特性和坡度对辽西低山丘陵区坡耕地褐土溅蚀的影响

为揭示辽西低山丘陵区坡耕地典型土壤溅蚀特征,选取褐土为研究对象,采用人工模拟降雨试验研究降雨特性和坡度对溅蚀的影响。结果表明:随着降雨强度的增大,5°和10°溅蚀量分别由6.86g/cm和8.13g/cm增加到14.21g/cm和16.00g/cm,增加幅度为48.47%~209.81%;不同溅蚀距离内的溅蚀量表现为0~5cm>5~10cm>10~15cm>15~20cm>20~25cm,溅蚀距离0~5cm范围内的溅蚀量(75mm/h)为7.29g/cm,占0~25cm范围内总溅蚀量(16.00g/cm)的45.56%,溅蚀距离20~25cm范围内的溅蚀量仅占9.88%。溅蚀量与降雨强度和溅蚀距离均具有较好的指数关系,其回归方程的决定系数R2在0.8以上。随着降雨时间的延续,溅蚀量逐渐增加,但溅蚀量增长率呈减小的趋势;降雨历时由5min增加到10min时溅蚀量增长率最大。溅蚀量和降雨历时之间具有较好的指数关系,其回归方程的决定系数R2在0.9以上。随着降雨强度发生变化时,溅蚀团聚体空间分布规律也随之发生改变。各径级团聚体的溅蚀距离均随降雨强度的增大而增大,2~5mm团聚体由30mm/h的0~5cm扩大到75mm/h的0~15cm。溅蚀团聚体以粒径<1mm为主,小粒径团聚体溅蚀距离和溅蚀量均大于大粒径团聚体,>5mm团聚体并没有迁移。5°总溅蚀量、上坡溅蚀量、下坡溅蚀量、净溅蚀量(75mm/h)依次为14.21,3.54,10.67,7.13g/cm,10°依次为16.00,3.85,12.15,8.30g/cm,与5°相比显著增加12.60%,8.76%,13.87%,16.41%,下坡溅蚀量大于上坡溅蚀量。

Effects of Rainfall Characteristics and Slope on Splash Erosion of Cinnamon Soil on Slope Farmland in Low Mountain and Hilly Region of Western Liaoning Province

In order to study the characteristics of typical soil splash erosion on slope farmland in low mountain and hilly region of western Liaoning Province, taking cinnamon soil as research object, the effects of rainfall characteristics and slope on splash erosion were studied by artificial rainfall simulation experiments. The results showed that with the increase of rainfall intensities, the splash erosion of 5° and 10° increased from 6.86 g/cm and 8.13 g/cm to 14.21 g/cm and 16.00 g/cm, respectively, with an increase range of 48.47% to 209.81%. The splash erosion with different splash distance was 0~5 cm > 5~10 cm > 10~15 cm > 15~20 cm > 20~25 cm. The splash erosion with splash distance at 0~5 cm with 75 mm/h was 7.29 g/cm, accounting for 45.56% of the total splash erosion (16.00 g/cm) in the range of 0~25 cm, and splash erosion with splash distance at 20~25 cm was only 9.88%. The splash erosion had a good exponential relationship with rainfall intensity and splash distance, and the determinant coefficient of the regression equation was above 0.8. With the extension of rainfall time, the splash erosion increased gradually, while the growth rate of splash erosion decreased. The growth rate of splash erosion was the largest when the rainfall duration increased from 5 min to 10 min. The splash erosion had a good exponential relationship with rainfall duration, and the determinant coefficient of the regression equation was above 0.9. Spatial distribution of splash aggregates changed with the changes of rainfall intensities. The splash distance of each diameter aggregate increased with the increasing rainfall intensities. The splash distance of 2~5 mm aggregate increased from 0~5 cm at 30 mm/h to 0~15 cm at 75 mm/h. Splash distance and splash erosion of small size aggregates were larger than that of large size aggregates. Splash aggregates were dominated by <1 mm aggregate, and >5 mm aggregate did not migrate. The total splash erosion, upslope erosion, downslope erosion, and net splash erosion of 5° with 75 mm/h were 14.21, 3.54, 10.67, and 7.13 g/cm, respectively, and which of 10° were 16.00, 3.85, 12.15, and 8.30 g/cm. Compared with 5°, the splash erosion of 10° increased by 12.60%, 8.76%, 13.87% and 16.41% respectively. The splash erosion on downslope was larger than that of upslope splash erosion.