赣县稀土采矿区巨桉林地土壤抗蚀性评价

通过野外调查与室内分析相结合，应用主成分分析法，从衡量土壤抗蚀性的16个指标中，优化得到赣县稀土采矿区巨桉林地土壤抗蚀性7个最佳评价指标：分散系数（X₁）、团聚度（X₂）、>0.25 mm水稳性团聚体含量（X₃）、>0.5 mm水稳性团聚体含量（X₄）、<0.05 mm粉黏粒含量（X₅）、>0.25 mm团聚体破坏率（X₆）和<0.001 mm黏粒含量（X₇），并以此为变量分析比较不同林龄巨桉林地土壤抗蚀性变化规律。结果表明：不同林龄巨桉林地土壤抗蚀性综合指数大小为：1年生林地>2年生林地>4年生萌芽1 a林地>裸露地。在此基础上，以上述7个评价指标为自变量，以土壤抗蚀性综合指数（Y）为因变量，进行回归分析，得出稀土采矿区土壤抗蚀性综合评价方程为：Y=0.309 X₁+0.038 X₂ -0.161 X₃ -0.643 X₄ +0.491 X₅ -0.032 8 X₆ +0.129 X₇ +41.637，因子决定系数R²=0.991 5，F=49.84，各因子间显著相关，方程拟合较好，可为构建稀土采矿区土壤抗蚀性评价指标体系提供依据。

Evaluation of Soil Anti-erodibility of Eucalyptus grandis Forest Land in Rare Earth Mining Area

Soil anti-erodibility is one of the important parameters for evaluating the ability of soil resistance to soil erosion. Based on the comprehensive investigation on soil physical and chemical properties, and incorporated into bioindicator, by using principal component analysis, all the 16 anti-erodibility indices could be optimized to 7 indices which were water-stable aggregates at size>0.5 mm and >0.25 mm, destructive rate of aggregates at size >0.25 mm, coefficient of dispersion, degree of aggregation, viscous grain powder at size 0.05 mm and viscous grain at size<0.001 mm. The laws of soil anti-erodibility variation of different aged Eucalyptus grandis are discussed and the result showed that the soil anti-erodibility index followed the order of one-year-old stand>two-year-old stand>four-year-old sprout stand>bare land. Taking the 7 indexes (X) as independent variables and soil erodibility index (Y) as dependent variable, the soil erodibility model equation in the rare earth mining area is: Y = 0.309X₁+0.038X₂ -0.161X₃ -0.643X₄ +0.491X₅ -0.032 8X₆ +0.129X₇ +41.637. The correlations among factors are significant and the model fits well.