1.Resources and Environment College, Huazhong Agricultural University, 430070, Wuhan, China; 2.Water Conservation Bureau County, 341000, Ganzhou, Jiangxi, China
Abstract：Collapsing erosion is the most serious erosion in the granite region of southern China, and has become one of severe geological disasters in China. Collapsing erosion produces a large amount of alluvial deposition in farmlands, causing desertification of alluvial fan farmland. In this study, we took the collapsing alluvial fan at Tian village in Ganxian County, Jiangxi Province as research object, collected soil samples from fan top to fan edge in different regions, and determined the composition of soil particles and spatial distribution of soil fertility in the collapsing alluvial fan area. The results showed that there is an obvious spatial heterogeneity in the distribution of physical and chemical properties of soil. From fan top to fan edge, the content of gravel and sand decreased, while that of silt and clay increased gradually, and soil fertility also showed a significant increase. Pearson correlation coefficient analysis showed that a significantly negative correlation existed between soil fertility and content of gravel and sand, whereas a significantly positive correlation could be observed between soil fertility and the content of silt and clay.The modified Nemerow composite index was adopted to evaluate the soil fertility in the alluvial fan area, and it indicated that the soil fertility fans increased gradually along fan top to fan edge. Compared to the soil at the fan top, the soil fertility level coefficient in the middle area and fan edge increased by 119.31% and 157.93%. Study of heterogeneous distribution of soil fertility benefits us in agricultural land use planning, and is of significance for improvement of soil and agricultural economy in collapsing alluvial fan areas.
2015, Vol. 13 
