ABSTRACT

Statistical methods were used to systematically analyze runoff plot data of Nihegou in Chunhua, Binxian, Huanglong, Yongshou, and Xifeng from 1964 to 1995. Based on these data and on 497 storm precipitation data, a basic equation for prediction of soil erosion on sloped cultivated land in the south Loess Plateau was derived. This equation is:

A basic runoff energy equation was proposed based on theoretical reasoning:

Using dimensional analysis and measured data correction, a dynamic model of soil erosion on homogenous slope area was developed:

INTRODUCTION

Eighty-three percent of cultivated lands on the Loess Plateau in China fall into the class called slope cultivated lands (Yang Wenzhi et al. 1992). Soil erosion on the slope cultivated lands is splash erosion, surface erosion, and rill erosion. Erosion accounts for 50-60% of total amount of sediment in the watersheds (Tang Keli, 1989; Huang Zhanbin, 1995). Accordingly, serious soil erosion has resulted in land deterioration, productivity decline and low and unstable grain yields, constraining the sustained development of agriculture in this region. Hence, much attention has long been paid to research on soil erosion laws on the slope cultivated lands. Based on measured data in runoff fields of Nihe Gully Watershed Chunhua County, southern Loess Plateau, along with data collected in adjacent areas, basic equations and dynamic models for soil erosion prediction for planning and realigning slope surface are established in this paper. Also, along the

methods of mathematical statistics and theoretical deduction, lay a solid foundation for further research.