南方红壤区农田道路强降雨侵蚀过程试验

Field Simulated Experiment on Erosion Processes of Different Farm Roads under a Heavy Rain in Red Soil Region

以南方红壤区江西水土保持生态科技园为研究区,通过野外调查选择4种典型农田道路(即裸露土路、碎石道路、泥结石路和植草土路)设置12个原位试验小区,采用人工模拟降雨试验研究了3.0 mm/min强降雨条件下农田道路侵蚀过程及特征。结果表明:被高度压实的农田道路产流时间短(小于2 min),并在2～6 min内径流趋于平稳,径流系数高达65%以上;农田道路产流初期侵蚀率较大,随后下降并在一段时间内趋于稳定。降雨后期,裸露土路路面出现细沟和微型切沟导致侵蚀率有所增大;与裸露土路相比,碎石道路、泥结石路和植草土路均可以改变路面径流的水力学特征,实现土质道路防护和减少侵蚀产沙的作用,减沙效益最低也可达40%左右,并以植草土路的水土保持效果最佳。

Totally 4 farm roads, i. e. the bare unpaved road, the stone covered road, the stone and grass covered road and the grass covered road, were selected on the representative area named Jiangxi Eco-scienee Park of Soil and Water Conservation. Twelve rainfall simulation experiments with an intensity of 3.0 mm/rnin were carried out on the selected roads. The results indicated that runoff from the farm roads was recorded less than 2 rain. The runoff rate increased quickly and reached steady level in the first 2 -6 min. The runoff coefficient was above 65%. The erosion rate was high at the beginning of the rainfall and then decreased due to the loss of fine soil surface particles and porosity changes. At later period, the erosion rate of the bare unpaved road increased to some extent due to the appearance of rill and micro-gully. Compared with the bare unpaved road, the stone covered road, the stone and grass covered road and the grass covered road can all change the runoff hydraulic characteristics, so to protect the farm roads and decrease sediment yield. The lowest benefit of sediment reduction was up to about 40% among them, and the grassed road had the best benefit of soil and water conservation.