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A Europium Tracer Method for Investigating Vertical Distribution of Loess Slopleland Soil Erosion

Abstract Soil erosion is a worldwide problem. Although there are a lot of investigations dealing with the problem, quantifying erosion through erosion plots is costly and labor intensive. Furthermore, the models used so far for quantifying the erosion are not satisfied. The specific objectives of this study were to set up a new erosion measure method by quantifying short‐term erosion and sedimentation and to develop spatial erosion distribution models. Europium (Eu) was chosen as a tracer atom. Positioning of soil‐core Eu tracer (PSCET) was established. Thirty total cores were put at six slope sections. Six cores were taken with the soil sampler in 3‐month intervals. Multiple linear regressions and multiple linear stepwise regressions were applied to models relationships between erosion and its factors. The PSCET was used on an acacia field. The field had natural and complex landforms with a length of 48 m and a width of 13 m. Erosion modulus increased with gradient and ranged from 85.7 to −9.8 t/hm2 for different slope sections. Temporal distribution of erosion was consistent with rainfall. Three months of July, August, and September accounted for 61.4% of the annual rainfall (518 mm) and for 90.1% of the annual soil loss on the acacia field in 2001. The correlations of erosion modulus to rainfall agent of erosion, slope length, and slope degree index were positive and to plant cover, organic matter, and clay particle contents were negative. The PSCET makes it possible to study spatial erosion and deposition distributions and to establish forecasting models.