草海上游石漠化过程中土壤抗蚀性变化

以草海流域上游的石漠化区为研究对象,研究不同等级石漠化条件下土壤抗蚀能力的差异,利用空间代替时间的方法,探讨草海上游区石漠化过程中土壤抗蚀性变化规律,为当地石漠化治理和湿地保护提供参考。通过实地调研,采集不同石漠化程度区的土样并进行室内指标测定,利用主成分分析方法选取了10个土壤理化指标对样地土壤抗蚀能力进行评价。结果表明:(1)所选10项理化指标可以较为全面地综合评价不同石漠化程度土壤抗蚀能力,土壤团聚状况、分散率、分散系数、0.25mm水稳性团聚体含量、0.5mm水稳性团聚体含量、结构破坏率、0.05mm粉黏粒含量这7项可以作为评价的优选指标,有机质含量、0.001mm黏粒含量、土壤团聚度这3项指标次之。(2)无石漠化CK样地(2.19)轻度石漠化L样地(1.19)重度石漠化S1样地(0.85)中度石漠化M样地(-1.35)重度石漠化S2样地(-2.88),其中中度石漠化样地(M)和重度石漠化样地(S_2)为负值,其余均为正值,差异明显。在石漠化过程中土壤抗蚀能力总体呈下降趋势,但是在石漠化发展后期,土壤抗蚀能力反而会有上升的可能。

Variation of Soil Anti-erodibility During Rocky Desertification in Upper Reaches of Caohai

We analyzed the differences between soil anti-erodibility under different rocky desertification conditions in karst rocky desertification region in upper reaches of Caohai.By using space instead of time,changes of soil anti-erodibility were investigated during rocky desertification in upper reaches of Caohai,aiming to provide reference for desertification control and wetland protection of Caohai.Soil samples from different karst rocky desertification level areas were taken according to field investigation.Soil physicochemical properties were tested in laboratory,and ten of them were selected to evaluate the soil anti-erodibility by principal component analysis with Spass 18.0.The results indicated that:(1) soil anti-erodibility under different rocky desertification conditions could be comprehensive evaluated by 10 indicators;the contents of silt/clay ＜0.05 mm,reunion situation,dispersion rate,dispersion coefficient,water-stable aggregates ＞0.25 mm,water-stable aggregates＞0.5 mm,structural damage rate were optimal indexes to evaluate soil anti-erodibility,and the indices organic matter,content of clay ＜0.001 mm,reunion degree came next;(2) the order of anti-soil erosion degrees of different rocky desertification areas obtained by principal component analysis was:sample CK of non rocky desertification(2.19)＞sample L of light rocky desertification(1.19)＞sample S1 of intense rocky desertification(0.85)＞ sample M of moderate rocky desertification(-1.35)＞ sample S2 of intense rocky desertification(-2.88),the values of comprehensive anti-erodibility indexes of Sample M and Sample S2 were negative,others were positive,the differences were obvious.Soil anti-erodibility declined gradually during rocky desertification,but it could also increase in late stage of rocky desertification.