南方红壤丘陵区杜仲人工林产流产沙与降雨特征关系

Relationships of runoff-and sediment yield under Eucommia ulmoides plantation in hilly red soil region of South China with rainfall characteristics

杜仲是我国南方红壤丘陵区重要的水土保持经济树种,为了阐明人工杜仲林地表径流和土壤侵蚀的特征及其与降雨特征的关系,2002—2005年在典型的杜仲人工林设置径流小区,进行定位观测,结果表明:1)观测期间,研究区主要以降雨量(R)<25mm、降雨强度(I)<5mm.h-1的降雨为主;2)降雨量(R)、降雨量与降雨强度的乘积(R.I)、降雨侵蚀力(R30)与土壤侵蚀量和径流均表现出极显著的线性相关关系;在对特定的降雨条件下的坡面侵蚀进行预测的时候,用R30进行预测比用R.I更接近通用土壤流失方程降雨影响因子的内涵;3)对杜仲人工林径流深(Rd)与降雨侵蚀力(R30)的乘积(Rd.R30)与土壤侵蚀量进行拟合,结果表明,二者达到极显著线性相关性(r=0.685,P<0.01),比单一用径流进行坡面侵蚀预测更符合水蚀产沙过程。

Eucommia ulmoides is an important economic and soil and water conservation tree species in hilly red soil region of South China. In 2002-2005, runoff plots were installed in a typical E. ulrnoides plantation to make observations, aimed to illustrate the relationships of surface runoff and soil erosion under E. ulmoides plantation with rainfall characteristics. In the observation pe- riod, the rainfall （R） and rainfall intensity （I） in most rain events were 〈25 mm and 〈5 mm·h^-1, respectively, and the runoff and soil erosion showed significant linear relationships with R, R · I, and rainfall erosivity （R30）. In a given rain event, R3o could be a better factor than R · I to predict slope erosion, and more approached to the connotation of Modified Universal Soil Loss Equation. The product of runoff depth （Rd） and R30, Rd · R3o, had a very significant linear correlation with the soil erosion under E. ulmoides plantation （ r = 0. 685, P 〈 0. 01 ） , suggesting its better ability than Rd for predicting slope erosion.