泥石流频发区不同林龄新银合欢土壤抗蚀性评价

Evaluation of soil anti-erodibility at different ages of Leucaena leucocephala forests in the area with high-frequency debris flow

土壤抗蚀性是评价土壤抵抗侵蚀能力的重要参数之一,植被恢复过程可引起土壤抗蚀性变化。本文通过野外调查与室内分析,运用主成分分析法对不同林龄新银合欢人工林土壤抗蚀性进行综合研究。结果表明:1)随着林龄的增长,新银合欢人工林土壤的通透性和结构稳定性变差,土壤细颗粒含量增加,土壤的养分含量有所降低;2)不同林龄新银合欢人工林土壤抗蚀性综合指数大小表现为:10年生>16年生>27年生,这说明随着林龄的增长,蒋家沟泥石流频发区新银合欢人工林土壤抗蚀性呈下降的趋势;3)表征土壤抗蚀性的13个指标可简化为:土壤密度、最大持水量、>0.25 mm水稳性团聚体含量、黏粒含量、粉粒含量5个指标,以此为自变量,以土壤抗蚀性综合指数为因变量,进行回归分析得出的评价模型为Y=-8.691X1+0.054X2+0.700X3-0.425X4-0.189X5-12.511,线性拟合程度较好。研究结果可为泥石流频发区土壤抗蚀性的后续研究及评价指标体系的构建提供参考。

Soil anti-erodibility is one of the important parameters for evaluating the ability of soil resistance to soil erosion. Aiming to understand the effect of vegetation restoration on soil erosion durability in the area with high-frequency debris flow, we determined the soil anti-erodibility at different ages of Leucaena leucocephala forests by using principal component analysis based on the data collected from the field and analyzed in the laboratory. The results showed that： 1 ） as the age of L. leucocephala forest increased, soil permeability, structure stability and soil nutrient decreased except for the content of fine particle ; 2） the comprehensive indexes of soil anti-erodibility followed the rule as 10 a 〉 16 a 〉 27 a, indicating that the soil anti-erodibility decreased with forest age in Jiangjia gully; 3 ） according to Pearson＇ scorrelations, all the 13 anti-erodibility indicators could be simplified to 5 indicators which were soil density, maximum water-holding capacity, the content of water-stable aggregates at size 〉 0.25 ram, clay content and silt content. Taking 5 selected indicators （X） as independent variables and soil anti- erodibility indicator （Y） as dependent variable, the soil anti-erodibility model was built by linear regression analysis as Y = - 8. 691X1 ＋ 0. 054X2 ＋ 0. 700X3 - 0. 425X4 - 0. 189X5 - 12.511. This result eould provide a reference for the building of soil anti-erodibility assessment indicator system and its future research in the area with high-frequency debris flow.