草本植物根系增强土壤抗剪切强度的量化研究  

Quantitative analysis of soil anti-shearing strength enhancement by the root systems of herb plants

作　　者：赵丽兵[1] 张宝贵[1] 苏志珠[2] 

机构地区：[1]中国农业大学资源与环境学院,北京100094 [2]山西大学黄土高原研究所,太原030006

出　　处：《中国生态农业学报》2008年第3期718-722,共5页Chinese Journal of Eco-Agriculture

基　　金：国家高技术研究发展计划(863计划)项目(2003AA209020)资助

摘　　要：通过对黄土高原丘陵沟壑区山西省河曲县砖窑沟流域内4种有代表性的草本植物进行野外剪切测试和模型预测，证实和量化了草本植物根系增强土壤抗剪切强度的作用。试验表明，在0～20cm土层4种草本植物根系均可显著增加土壤抗剪切强度，其中紫花苜蓿根系对土壤抗剪切强度的增强作用最大，其增大土壤抗剪切强度值为15．33kPa；草木樨和紫花苜蓿根系在20～40cm土层也能明显增大土壤抗剪切强度。同时，对比分析了实测结果与模型预测值间的差异，认为根系增大土壤抗剪强度的真实值应介于实测值和预测值之间。研究结果也表明这4种草本植物根系均具有较高的抗拉强度，且根系的抗拉强度与直径间存在显著幂函数负相关关系。这些研究对黄土区预测和评估草本植物根系的固土护坡作用，以及水土保持植物的选择及优化组合，更有效地发挥植物根系生物软措施的固土潜能具有重要现实指导意义。Shallow soil anti-shearing strength enhancement was verified and quantified in the Loess hill gully area of Zhuanyaogou watershed, Hequ County, Shanxi Province, through in-situ direct shear-strength test and modeling of 4 representative herb plants. In 0 -20 cm soil layer, there is a considerable effect of herb plant root system on soil anti-shearing strength. Soil anti-shearing intensity （ 15.33 kPa） by Medicago sativa is highest. Particularly in the 20 -40 cm soil layer, Melilotus officinalis and M. sativa can drastically enhance soil anti-shearing strength. Meanwhile analysis of the difference between model prediction and field observed values for soil anti-shearing strength enhancement by plant shows the true value to be between the two. The research shows that the 4 herb plants root systems own strong tensile strength and has negative correlation with the root diameter. The research has significant implication in forecasting and the appraising soil reinforcement by herb root system in loess regions. With regard to the choice and optimal organization of soil and water conserving plants, the research may provide a theoretical guidance on potential soil reinforcement capacity by plant root system.

关 键 词：草本植物根系 抗拉强度 剪切强度 生物软措施 固土护坡 

分 类 号：S157.2[农业科学—土壤学]