تخمین پاسخ فرسایش خاک در استفاده از زمین
Abstract
1- Introduction
2- Catchment description and data collection
3- Methods and datasets
4- Results
5- Conclusion
Acknowledgements
References
Abstract
The vegetation restoration project, named the Grain to Green Program, has been operating for more than ten years in the upper reaches of the Beiluo River basin, located in the Loess Plateau of China. It is significant to be able to estimate the success of preventing soil erosion. In this study, the Revised Universal Soil Loss Equation (RUSLE) and the Sediment Distributed Delivery (SEDD) model were used to assess the annual soil loss derived from water erosion. The results showed that the study area suffered from primary land use changes, with increasing grassland and forest and decreasing farmland from 1990 to 2010. Based on that, the average soil erosion modulus decreased from 18,189.72 t/(km2 a) in 1990– 7408.93 t/(km2 a) in 2000 and 2857.76 t/(km2 a) in 2010. Compared with 1990, the average soil erosion modulus decreased by 59.0% and 84.3% for 2000 and 2010, respectively. Benefiting from the increased vegetation coverage and improved ecological environment, the soil erosion in this study area clearly declined. This research also found that the distribution of the three years of soil erosion was similarly based on topographic factors. The soil erosion modulus varied with different land use types and decreased in the order of residential area4farmland4grassland4forest. The average soil erosion modulus gradually increased with the increase of the slope gradient, and 76.08% of the total soil erosion was concentrated in the region with a gradient more than 15 degrees. The soil erosion modulus also varied with slope aspects in the order of sunny slope4half-sunny slope4half-shady slope4shady slope. This research provides useful reference for soil and water conservation and utilization in this area and offers a technical basis for using the RUSLE to estimate soil erosion in the Loess Plateau of China.
Introduction
Soil erosion, a widespread form of soil degradation, is one of the most severe threats to the terrestrial ecosystems in the world (Pimental, Harvey, & Resosudarmo, 1995). It is directly related to decreased agriculture productivity and water pollution, and it has many negative effects on nature, such as degradation of soil structure, depletion of soil fertility, reducing the effective rooting depth, and ruining the most fundamental of all natural resources (Fitton, Saffouri, & Blair, 1995; Lal & Bruce, 1999; Nearing, 2005). The Chinese Loess Plateau is the most heavily eroded area in the world (Fu, 1989), and the soil erosion modulus with 5000– 10,000 mg km2 per year were larger than other areas (Chen, Wang, Fu, & Qiu, 2001). Since the 1950s, to control severe soil erosion, improve agriculture production and reduce sediment loads in the Yellow River, there has been implemented a lot of soil and water conservation projects in the Loess Plateau catchments.