中文摘要：

崩岗侵蚀是南方花岗岩地区最严重的侵蚀方式,已成为我国一种严重的环境地质灾害,尤其是崩岗侵蚀产生的大量洪积物沉积在农田中,造成洪积扇农田沙化。以赣县田村镇崩岗洪积扇为研究对象,采集扇顶到扇缘不同区域的土样,研究该地区崩岗洪积扇土壤颗粒组成及土壤肥力的分异规律。结果表明：崩岗洪积扇土壤理化性质在空间分布上具有明显的分异规律。由扇顶到扇缘,土壤砾石和砂粒质量分数均逐渐减少,粉粒和黏粒质量分数则逐渐增加,土壤肥力也随之呈显著增加趋势。利用Pearson相关系数分析显示,土壤肥力与土壤砾石和砂粒质量分数呈显著负相关,而土壤肥力与粉粒和黏粒质量分数呈显著正相关。采用修正的内梅罗综合指数法对洪积扇土壤进行肥力评价发现,土壤肥力沿扇顶到扇缘逐渐增加,相比于扇顶土壤,扇中、扇缘土壤肥力等级系数分别增加了119.31%和157.93%。研究崩岗洪积扇土壤肥力分异规律有利于农业用地规划,对崩岗洪积扇土壤改良和提高农业经济效益有重要意义。

英文摘要：

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 by119. 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.