青海湖流域土壤大孔隙特征与理化性质的相关性研究

摘要

Soil macropores are preferential pathways for water, air and chemical substances movement in soils. Undisturbed soil columns under different vegetation types were sampled in Shaliu River Basin of the Qinghai Lake and scanned with X-ray computed tomography. And 3D soil macropore networks were visualized and macropore quantity, macroporosity and equivalent diameter were interpreted with Fiji software through reconstruction. Then the correlations between soil physical-chemical properties and macropore characteristics were studied. The results indicated that soil macropores were mainly distributed in the 0–100 mm layer of soil, soil phosphorus was significantly correlated with number and mean equivalent diameter of macropores, soil nitrogen and organic matter were significantly correlated with mean equivalent diameter of macropores, soil bulk density was significantly correlated with macroporosity and mean equivalent diameter of macropores, and soil particles of 0.002–0.02 mm was correlated highly with soil macropore characteristics.%土壤大孔隙是土壤水分、空气和化学物质运移优先流的主要途径.本文以青海湖流域土壤为研究对象,在青海湖沙柳河流域取原状土柱,利用CT扫描与Fiji软件相结合的方法,实现了土壤大孔隙结构的三维可视化,以及断层横截面土壤大孔隙度、大孔隙数量和大孔隙等效直径等的量化;并探讨了样地土壤大孔隙特征与理化性质的相关性.结果表明:青海湖流域土壤大孔隙主要分布在土壤表层0~100 mm,100 mm以下大孔隙较少;土壤全磷含量分别与土壤大孔隙数量、大孔隙等效直径有显著相关性;土壤全氮、有机质含量分别与土壤大孔隙平均等效直径有显著相关性;土壤体积质量与大孔隙度、大孔隙平均等效直径等有显著相关性;土壤中0.002≤Ф<0.02 mm的颗粒含量与大孔隙的分布特征相关性较大.