内蒙古典型草原灌丛化与土壤性质的关系研究

Relationship between shrub encroachment and soil properties in the typical steppe of Inner Mongolia

本文以内蒙古典型草原区有灌丛入侵及无灌丛入侵现象草地为研究对象,探讨了土壤性质与草原灌丛化现象间的关系。研究结果表明:在围封状态下,无灌丛化草地土壤粉粒、粘粒及养分(有机质、全氮、全磷)含量在0～60cm深度均显著高于灌丛化草地,而土壤容重、砂粒则显著低于灌丛化草地,且二者的差异随着土壤深度的增加而增大;在重度放牧状态下,各指标的变化趋势与围封状态相同,但差异性仅在表层0～10cm显著。草原灌丛化与表层土壤砂粒、容重呈显著正相关性,与土壤粉粒、有机质、全氮、全磷含量呈极显著负相关性。以上结果说明,草原灌丛化的出现与其分布生境的土壤特点有关。相比于草本而言,灌木在粗质贫瘠土壤中更具有竞争性。

The aim of this study was investigate the soil properties of shrub-encroached grassland and non-encroached grassland in Inner Mongolia.Compared with the non-encroached grassland,shrub-encroached grassland had higher soil bulk density and sand content,and lower silt,clay,organic matter,total nitrogen,and total phosphorus in the 0-60 cm soil layer.The differences in soil composition and soil nutrient contents were significant in the 0-60 cm soil layer in the enclosed treatment and in the 0-10 cm soil layer in the heavy grazing treatment.The extent of shrub encroachment was significantly and positively correlated with sand content and bulk density,but significantly and negatively correlated with soil grain size distribution and soil nutrient content.The above results suggest that soil properties have important effects on shrub encroachment.Poor and coarse-textured soil may be beneficial for shrub establishment and growth.