路基边坡草灌植被消减降雨侵蚀作用机理探讨

Discussion on action mechanism that rainfall erosivity R value was decreased by grass-shrub vegetation on subgrade slope

为深入探讨草灌植被消减降雨侵蚀作用机理,提高其生态防护效益,2005～2008年,选择路基边坡不同土壤类型和草灌植被为研究对象,通过野外径流小区法和数据分析,探讨了边坡草灌植被消减降雨侵蚀作用机理。结果表明:(1)降雨侵蚀力被草灌植被消减效果得到量化,植被覆盖度越大,效果越好;(2)降雨侵蚀力R值与土壤流失量正相关,建立了二者幂函数关系式;(3)边坡植被保持水土效果:砂姜黑土:紫花苜蓿93.1%,高羊茅92.3%,紫穗槐91.8%,狗牙根88.0%,小叶扶芳藤77.9%;黄粘土:紫穗槐96.6%,紫花苜蓿95.8%,高羊茅95.4%,小叶扶芳藤94.6%,狗牙根89.1%;粉砂土:高羊茅91.8%,紫花苜蓿90.7%,狗牙根87.3%,紫穗槐84.2%,小叶扶芳藤82.4%。该成果对路基边坡生态防护具有实际指导作用和理论价值。

To increase the benefits of ecological protection,the research was made on the action mechanism,of grass-shrub vegetation which decreased the rainfall erosivity,we chose different soil types and vegetation types on subgrade slope as the object of study from 2005 to 2008,discussion on action mechanism that rainfall erosivity R value was decreased by the field runoff-plots and data analysis in different types of soil and vegetation.The results reveal：（1） Quantifies the rainfall erosivity R value was decreased by grass-shrub vegetation on subgrade slope,vegetation coverage bigger that effect is always better;（2） The soil erosion amount was positively correlated with the rainfall erosivity R value.the power functional relationship between them is established;（3） The action effect which conserve soil and water of shrub-grass vegetation on subgrade slope ： Black soil with lime concretions： Medicago sativa 93.1 %,Festuca arundinacea 92.3 %,Amorpha fruticosa 91.8 %,Cynodon dactylon 88.0 %,Euonymus fortuneivar 77.9 %;Yellow clay： Amorpha fruticosa 96.6 %,Medicago sativa 95.8 %,Festuca arundinacea 95.4 %,Euonymus fortuneivar 94.6 %,Cynodon dactylon 89.1 %;Powder sandy soil： Festuca arundinacea 91.8 %,Medicago sativa 90.7 %,Cynodon dactylon 87.3 %,Amorpha fruticosa 84.2 %,Euonymus fortuneivar 82.4 %.Which could service as practical guidelines and theoretical value for ecological protection in expressway side slope.