滇中亚高山林地土壤团聚体结构及其对优先路径的影响

Soil Aggregate Structure of Subalpine Woodland and Its Influence on Priority Path in Central Yunnan

[目的]分析滇中亚高山林地土壤团聚体结构对土壤优先路径形成的影响,揭示林地土壤优先路径的形成与发生机理,深化对森林生态系统土壤水文过程的认识,为滇中林区水源涵养林建设、天然林植被恢复与重建提供科学依据。[方法]选取滇中亚高山云南松林、华山松林、滇油杉林、高山栎林4种林地土壤为研究对象,利用染色示踪法,结合Photoshop CS 5、Image Pro Plus 6.0、Surfer 15图像处理软件提取土壤优先路径,同时系统评价土壤团聚体结构特征,采用相关分析、主成分分析、灰色关联分析、耦合度分析等方法探讨土壤团聚体结构对优先路径的影响。[结果](1)研究区4种林地土壤具有良好的团聚体结构,结构稳定性依次为:华山松林>滇油杉林>云南松林>高山栎林,土壤团聚体结构受林地类型、土层深度的影响显著(P<0.05),且与不同粒级水稳定性团聚体含量有相关性。(2)林地土壤优先流具有优势性,华山松林优先路径的连通性优于云南松林、高山栎林和滇油杉林,优先路径数量随着土层深度增加逐渐减少。(3)粒径>0.25 mm水稳定性团聚体含量(WSA)、平均质量直径(MWD)、几何平均直径(GMD)、平均质量比表面积(MWSSA)、结构体破坏率(PAD)、分形维数(D)能较好地评价土壤团聚体结构特征,与优先路径数量的关联度>0.62,属于中等关联,是影响优先路径形成的重要因素。(4)滇中亚高山林地土壤团聚体结构与优先路径数量的平均耦合度为0.683,系统属于弱协调,耦合协调程度依次为:0.728(云南松林)>0.681(华山松林)>0.663(高山栎林)>0.662(滇油杉林)。[结论]土壤团聚体结构是影响土壤优先路径形成与发生的重要因素,但对优先路径的产生不起决定性作用。

[Objective]To analyze the influence of soil aggregate structure on the formation of soil priority path for subalpine woodland in central Yunnan for providing scientific basis for the construction of water conservation forest,the restoration and reconstruction of natural forest vegetation in central Yunnan forest area.[Method]Based on four subalpine woodland soils of Pinus yunnanensis forest,Pinus armandii forest,Quercus semecarpifolia forest and Keteleeria evelyniana forest in central Yunnan,the soil priority path was extracted by using dye tracing method,combined with Photoshop CS 5,image pro plus 6.0 and surfer 15 image processing software.The structural characteristics of soil aggregates were systematically evaluated,and the effect of soil aggregate structure on priority path was explored by correlation analysis,principal component analysis,grey correlation analysis and coupling degree analysis.[Result]Results showed that:(1)the soil of four subalpine forest lands in the study area had good aggregate structure,and the structural stability in the P.armandii forest was the largest,followed by K.evelyniana forest,P.yunnanensis forest,and Q.semecarpifolia forest.The soil aggregate structure was significantly affected by forest land type and soil depth(P<0.05),and it was correlated with the content of water stable aggregates in different particle sizes.(2)The preferential flow of forest land soil had advantages.The connectivity of priority paths in P.armandii forest was better than that of P.yunnanensis forest,Q.semecarpifolia forest,and K.evelyniana forest.In addition,the number of priority paths gradually decreased with the increase of soil depth.(3)The content of water stable aggregates with particle size>0.25 mm(WSA),mean weight diameter(MWD),geometric mean diameter(GMD),mean weight soil specific area(MWSSA),percentage of aggregate destruction(PAD)and fractal dimension(D)could better evaluate the structural characteristics of soil aggregates.The correlation with the number of priority paths was more than 0.62,which was important factor affecting the formation of priority paths.(4)The average coupling degree between soil aggregate structure and the number of priority paths for subalpine forest land in central Asia was 0.683,and the system belonged to weak coordination.The coupling coordination degree in P.yunnanensis forest was the largest(0.728),followed by P.armandii forest(0.681),Q.semecarpifolia forest(0.663),and K.evelyniana forest(0.662).[Conclusion]Soil aggregate structure is an important factor that affects the formation and occurrence of soil priority path,but it does not play a decisive role in the formation of priority path.