Effects of Tillage Erosion on Soil Nutrients in Loess Sloping Land of China

The effects of tillage erosion on soil nutrients in Loess sloping land of China were studied with topography measurement, ¹³⁷Cs tracing, analysis of soil properties, and repeated tillage. The results show that spatial variations of total nitrogen, available nitrogen and organic matter with horizontal slope length can be described with parabola, and that spatial variations of available phosphorus and available potassium with horizontal slope length can be described with power function. Relationships between tillage erosion and total nitrogen, available nitrogen and available potassium can be described with linear equation, and the relationship between tillage erosion and available phosphorus can be described with cubic polynomial. Contributions of tillage erosion to total nitrogen, available nitrogen, available phosphorus and available potassium are 16.47%, 2.69%, 48.85% and 15.30%, respectively. With tillage erosion, the available nitrogen, available potassium, organic matter and cation exchanging capacity will decrease the tillage erosion area and increase tillage deposition area of hillslope in 15 years.