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在重庆市忠县石宝镇选择桑树林地,每隔10 cm分层采集土壤样品,分离桑树根系与土壤,利用根系分析系统WinRHIZO分析根系的长度、体积和表面积等指标,同时测定紫色土土壤抗剪强度、紧实度、水分含量和容重等指标,利用逐步回归分析从形态学角度评价桑树根系对紫色土土壤抗剪强度的影响。结果表明:桑树根系根长密度总体上随土壤深度的增加而减少,中根及小根根体积密度随土壤深度的增加而增加,细根及极细根表面积密度则随土壤深度增加而减少;桑树林地土壤抗剪强度总体上随土壤深度的增加而增加,10—40 cm层林地土壤抗剪强度显著高于同层对照;紫色土土壤抗剪强度增加值主要来源于桑树平均根体积密度和土壤水分增加值的贡献,且前者是主要贡献者,桑树根系可以有效提高紫色土土壤抗剪强度。
In Shibao Town, Zhongxian County, Chongqing, the mulberry woodland was selected. The soil samples were collected every 10 cm. The roots and soil of mulberry were separated. The root length, volume and surface area were analyzed by root analysis system WinRHIZO. Shear strength, compaction degree, moisture content and bulk density, etc. The morphological analysis was used to evaluate the effect of mulberry root on the shear strength of purple soils. The results showed that the root length density of mulberry root decreased with the increase of soil depth. The root density of mulberry root and small root increased with the increase of soil depth, and the surface density of fine root and fine root decreased with the increase of soil depth. The shear strength of soil in forestland generally increases with the depth of soil, and the shear strength of soil in 10-40 cm layer is significantly higher than that of the same layer. The increase of shear strength of purple soil mainly comes from the average root volume density of mulberry and soil The contribution of water added value, and the former is the main contributor, mulberry roots can effectively improve purple soil shear strength.