The hilly region of red soil in southern Jiangxi is being faced with serious soil erosion and land degradation. In this study, we took the Nanfeng County as a case study to explore the relationships between soil erosion and nutrient elements under wetland pine forest, orange orchard and paddy field using the ¹³⁷Cs tracer approach. The results showed that:(1) There were significant differences in the distributions of ¹³⁷Cs and nutrient elements in soil with the three land use types. The contents of ¹³⁷Cs in soil of wetland pine forest decreased exponentially along with the vertical profile. While in the soils of orange orchard and paddy fields, the ¹³⁷Cs was evenly distributed in the plough layer due to human disturbance. The distribution of organic matter was similar with ¹³⁷Cs. The contents of total nitrogen, alkali nitrogen, available phosphorus and available potassium in the three land use types showed obvious accumulation in surface layer. (2) In the soil of hillside wetland pine forest, the contents of ¹³⁷Cs, total nitrogen, alkali nitrogen, available phosphorus, available potassium and organic matter were characterized by:downhill > uphill > mid-slope. While in the orange orchard soil, the activities of ¹³⁷Cs were mid-slope > downhill > uphill. The contents of total nitrogen, alkali nitrogen and available phosphorus showed downhill > mid-slope > uphill. And the maximum contents of available potassium and organic matter were found on the uphill. (3) Correlation analysis showed that ¹³⁷Cs was positively correlated with organic matter, total nitrogen and alkali nitrogen, indicating that organic matter and nitrogen in small watershed might have the same physical migration mode as ¹³⁷Cs. The pH value was significantly negatively correlated with ¹³⁷Cs. While there were no significant correlations between the contents of available phosphorus and available potassium and ¹³⁷Cs. (4) Among the three land use types, the ¹³⁷Cs, organic matter, total nitrogen and alkali nitrogen contents in the paddy field of the small watershed valley were the highest. On the hillside, the contents of ¹³⁷Cs and soil nutrient elements in the orange orchard were higher than those in the wetland pine forest, indicating that the changing slopping-to-terraced orange planting patterns could effectively alleviate soil erosion and nutrient loss, and improve the regional ecological environment.