坡度与种植方式对紫色土侵蚀与养分流失的影响研究

在涪陵区水土保持监测分站内建立6个径流小区,对紫色土坡耕地水土流失进行试验监测,结果表明:各小区径流量、产沙量总体随降雨量的增大而增大.自然生态修复措施防治水土流失效果显著,3.66 m3的径流量仅有0.41 kg·m3的产沙量,可有效防治紫色土坡耕地的水土流失.采用顺坡耕作措施的小区径流量与降雨量达显著正相关,而产沙量与降雨量未显著相关.径流量和产沙量大小顺序均为25°坡耕地>20°坡耕地>10°坡耕地>15°坡耕地,在15°耕地上径流量与产沙量均为最小,但15°是否是涪陵区最适宜的耕地坡度,仍有待今后收集更多的降雨资料加以分析说明.对一次强降雨进行养分流失观测,养分流失量与径流量及产沙量大小顺序基本一致.开发建设项目弃土弃渣监测点径流量与产沙量均大大高于其他小区,说明开发建设水土保持项目中防治水土流失的重要性.

Effect of slope and planting mode on erosion and nutrient loss in purple soils

Based on the six runoff plots built at the soil and water conservation monitoring station in Fuling, the soil and water loss on cultivated purple soil slopes was investigated. The results show that plot runoff and sedimentation increase with increasing rainfall. Environmental rehabilitation reduces soil and water loss with only 0.41 kg·m^-3 sediment from 3.66 m³ runoff, an effective control measure of soil and water loss on cultivated purple soil slopes. On cultivated plots which in sequence with slope, evident positive correlations exist between runoff and rainfall, but with less evident correlation between sediment and rainfall. Runoff and sediment decreases with decreasing slope degree. 15° slope plough is most environmental friendly, but as to whether it is most suitable for cultivation in Fuling area is subject to further rainfall data analysis. In one strong rainfall observation, the sequence of soil nutrient loss is almost consistent with runoff and sediment. Runoff and sediment on monitoring plots with waste residue of building material are much higher than on other plots, indicating it is important to prevent soil and water loss on soil-water -conservation engineering.