放牧对贝加尔针茅草原植被根系分布和土壤理化特征的影响

Effects of grazing on plant root distribution and soil physicochemical properties in Stipa baicalensis grassland

以内蒙古贝加尔针茅草原为研究对象,分析了放牧对植被根系分布特征的影响及其与土壤理化性状的相互关系。结果表明:放牧导致植被根系分布发生显著变化;0～10cm土层根系生物量占0～40cm根系总生物量的65.9%～82.6%,直径≥2mm根系和直径<1mm的根系对放牧影响较为敏感;植被根系分布与土壤容重、含水量、全氮、全磷、有机碳含量以及阳离子交换量有一定程度的相关性,放牧主要通过改变土壤理化特征影响不同径级根系生物量的分布,同时各径级根系分布特征对土壤理化性状有一定的反馈作用。

A field experiment was conducted on the Stipa baicalensis grassland in Inner Mongolia to study the effects of grazing on plant root distribution,and analyzed the correlations of the root distribution with soil physicochemical properties. Grazing induced a significant change in root distribution. The root biomass in 0-10 cm soil layer accounted for 65.9%-82.6% of the total biomass in 0-40 cm soil layer. The roots with diameter ≥2 mm and 1 mm were more sensitive to grazing. The root distribution had definite correlations with soil bulk density,moisture content,contents of total nitrogen,phosphorus,and organic carbon,and cation exchange capacity. Grazing affected the distribution of plant roots with different diameters mainly through affecting soil physicochemical properties,and the characteristics of the root distribution had certain feedback on the soil physicochemical properties.