放牧对高寒草甸地表特征和土壤物理性状的影响

在中国科学院海北高寒草甸生态系统定位站地区,选择五种处于不同放牧强度的高寒草甸为研究对象,进行放牧对高寒草甸植被演替规律和土壤对放牧压力的响应过程研究,为合理利用和提高草地生产力提供科学依据。结果表明:随着放牧强度的增加,高寒草甸地上生物量呈急剧下降趋势,由禾草草甸的646.24 g/m2下降到小嵩草草甸的328.16 g/m2,容重逐渐减小;在小嵩草草甸阶段地表逐渐出现塌陷和裂缝,0~10 cm土层中根土体积比逐渐变大;土壤的质地类型发生变化,由禾草草甸粘壤土转变为壤质粘土;放牧强度对牧草返青开始时间和生长期都没有影响,但在重牧处理时,非生长季地温降低程度很明显。

Effect of Grazing on Surface Character and Soil Physical Property in Alpine Meadow

Five kinds of alpine meadow under different grazing intensity were selected as research plot for studying disturbance of grazing to alpine meadow vegetation succession rule and soil response process to grazing intensity at Haibei ecosystem research station,Chinese Academy of Sciences.The pasture maintained relatively stably grazing intensity and formed obvious grazing grads on surface character and species component.The time of the experiment was from July,2005 to September,2006.The grazing intensity was obtained by investigating livestock quantity and field acreage.It provided the scientific basis for reasonable use and enhancing the grassland productive forces.The results showed that the biomass declined rapidly which from 646.24 g/m2 to 328.16 g/m2,soil bulk density changed slightly,and more dent and cranny were appeared at Kobresia pygmaea meadow;the rate of root/soil volume at 0~10 cm enhanced gradually;the type of soil texture changed from clay loam to loam clay with grazing intensity increasing.There are no differences on the time of seedling establishment and growth period between light grazing intensity treatment and high grazing intensity treatment.The change of soil temperature was more significant on high grazing intensity than that on high grazing intensity in non-growth season.