Using 137Cs measurements to investigate the impact of soil erosion on soil nutrients in alpine meadows within the Yangtze River region, China

In this study, the 137Cs technique was used to study soil erosion and its impact on soil nutrients in an alpine meadow area of the upper Yangtze River. The results show that soil erosion significantly affects the redistribution of soil organic carbon (SOC), total nitrogen (N) and total phosphorus (P). To characterize the distribution and dynamics of 137Cs, SOC, total N and total P in the intensively eroded soil, the SOC, total N, total P stocks and 137Cs were measured in a reference plot derived from values extracted at Beiluhe Basin. More than 90% of 137Cs were concentrated in the upper 0-10 cm of the soil profile within the reference plot, presenting an exponentially decreasing distribution with depth along the whole profile (R2 > 0.8). Soil nutrient content and distribution changed noticeably after the soil eroded. The top 0-5 cm of the soil profile lost 65%, 70%, 67% and 12% of 137Cs, total N, SOC and total P respectively. 137Cs increased from 58% to 70% at depths of 10-20 cm and 20-30 cm, whereas total N and SOC values decreased from 77% to 25%. During the process of erosion, there is a close relation between 137Cs changes and SOC, total N and total P values.