紫色土坡耕地香根草根系的固土抗蚀效应

Soil erosion control effectiveness of Vetiveria zizanioides root system in the purple soil cropland

本试验以坡度3°和25°下的自然生草和香根草(Vetiveria zizanioides)为研究对象,采用室内直剪试验和原状土冲刷试验,分析紫色土坡耕地上香根草根系的固土抗蚀效应。结果表明,1)香根草根系改变了土壤结构,土壤容重与根长密度、根表面积密度极显著负相关(P<0.01),与根重密度显著负相关(P<0.05),土壤含水率与根长密度、根表面积密度显著正相关;2)土壤抗剪强度与根重密度、根表面积密度极显著正相关,与根长密度、含水率显著正相关,土壤抗冲性指数与根重密度、根长密度和根表面积密度极显著正相关;3)同级荷载(100、200、300、400 k Pa),土壤抗剪强度表现为,香根草3°>香根草25°>自然生草3°>自然生草25°,土壤抗冲指数表现为,香根草3°>香根草25°>自然生草3°>自然生草25°;4)与自然生草相比,含香根草土体结构稳定,抗剪、抗冲能力强,在3°和25°坡耕地上均表现出一定的固土抗蚀效应。

The direct cutting natural grass and vetiver grass(Vetiveria zizanioides) and the washing undisturbed soil experiments were used to analyze the soil erosion effect of their root system at the slope of 3° and 25° of purple soil.Results showed that: 1) The vetiver root system altered the soil structure,indicating that the soil bulk density was significantly negative correlated with root length density and surface area density(P<0.01) and was significantly negative correlated with root weight density(P<0.05),and the soil water content had significantly positive correlation with root length density and root surface area density(P<0.05).2) Soil shear strength had significantly positive correlation with root weight density and root surface area density(P<0.01),also had significantly positive correlation with root length density and soil water content; And soil anti-scouribility index had significantly positive correlation with root weight density,root length density and root surface area density(P<0.01).3) Under the same load strength(100,200,300,400 k Pa),shear strength showed as vetiver grass 3°>vetiver grass 25°>natural grass grass 3°>natural grass 25°; On different experimental plot,soil antiscouribility index showed as vetiver grass 3°>vetiver grass 25°>natural grass 3°>natural grass 25°; 4) Compared with the natural grass,soil structure with vetiver was more stable,and had stronger ability of shear strength and soil antiscouribility; And the vetiver showed the soil erosion effect in sloping cropland of 3° and 25°.