Application of the 137Cs tracer technique to study soil erosion of alpine meadows in the headwater region of the Yellow River

Abstract

The Cs-137 tracer technique was used to study soil erosion of alpine meadow grassland in two small river basins in the headwater region of the Yellow River. The results show that the levels of Cs-137 in soil samples from this alpine meadow vegetation zone exhibit an exponential distribution, generally within a depth of approximately 20 cm. Due to strong winds, freeze-thaw cycles and water, soil erosion was found to be stronger on the upper slope than on the lower slope, and except for the slope crest, the intensity of soil erosion at other sites was as follows: upslope < midslope < downslope. There was a significant negative correlation between the intensity of soil erosion and the extent of alpine meadow vegetation cover (P < 0.01). The mean soil erosion modulus exhibited a linear reduction trend with an increase in vegetation cover, and the correlation coefficient R (2) was a parts per thousand yen 0.997. The higher the degradation degree of the alpine meadow grassland, the greater is the soil erosion. The mean erosion modulus in the severely degraded meadow zone was 2.23 times greater than the one in the slightly degraded zone, and the maximum erosion modulus reached 2.96 x 10(6) kg/km(2)/a.