藏东南高寒区尼洋河河谷地带不同土地利用方式土壤抗蚀性研究

土壤抗蚀性是评价土壤侵蚀潜在发生可能性的重要综合性指标,研究高寒河谷地带不同土地利用方式土壤抗蚀性为土地利用模式优化和资源整合提供理论依据.本文应用主成分分析法对藏东南高寒区尼洋河流域5种不同土地利用方式下的3大类、13个土壤抗蚀性指标进行分析研究.研究结果表明:土壤团粒类指标和有机质能很好地反映土壤抗蚀性,0.25 mm水稳性团聚体质量分数、0.5mm水稳性团聚体质量分数、0.25 mm非水稳性团聚体质量分数、水稳性指数、平均重量直径、团聚体结构破坏率、有机质7个指标对土壤抗蚀性的影响最为明显,是表现不同土地利用方式土壤抗蚀性的最佳指标.各抗蚀性指标值基本表现出(0～15)cm(16～30)cm规律.通过建立权重求和模型发现0～15 cm表层土壤抗蚀性能远远大于16～30 cm;最终,通过叠加法得出不同土地利用类型土壤抗蚀性评价从强到弱顺序为:灌木林地(SL)、天然林地(NF)、农耕地(CL)、河滩林地(BL)、人工林地(AF).

Soil Anti-erodibility of Different Land-Use Modes in Niyang River Watershed of Alpine Region in Southeastern Tibet

Soil anti-erodibility is an important comprehensive indicator to evaluate the potential probability of soil erosion. It will provide a theoretical basis to study soil anti-erodibility of different land-use in river valley region of alpine for optimizing land-use models and integrating resources. In this study, 13 indexes about soil anti-erodibility have been analyzed by principal component analysis, which belonged to three major categories in five different land-use patterns in Niyang Watershed of Alpine Region in Southeastern Tibet. The results show that indexes of soil aggregate class and organic matter could reSLect soil anti-erodibility. Seven indexes of > 0.25mm water stable aggregate content, > 0.5mm water stable aggregate content, > 0.25mm non-water stable aggregate content, water stability index, average weight diameter, aggregate structure failure rate, and organic matter had the most obvious inSLuence on soil anti-erodibility, and they were the best indicators which reSLected soil anti-erodibility in different land-use ways. The index values of soil anti-erodibility show the orderliness that the values in the layer from 0 to 15 cm were larger than those in the layer from 15 to 30 cm. It was found by establishing the weight sum model that the soil anti-erodibility of the surface layer from 0 to 15 cm was much greater than that of the layer from 15 to 30 cm. Finally, the descending order of soil anti-erodibility ofdifferent land-use types was concluded:Fallow land > Natural woodland > Cultivated Land > Riverbank woodland > Artificial forest land.