Based on the study of succession dynamics and processes of restoration of the degraded grassland community of Leymus chinensis to evaluate effect of fencing. Dry and fresh community biomass were measured with quadrate method. The results showed that the dry-to-fresh biomass ratio was in rising trend with the fluctuation during the study period, which may be explained by two factors: fluctuations in precipitation and difference in species at different succession stage. The highest dry-to-fresh ratio was observed in grasses family followed by compositae and legumes. Changes in the ratio can indicate important changes and trends in vegetation dynamics. Overall, the dry-to-fresh biomass ratio changed significantly (0.45) which was driven mainly by Leymus chinensis, Agropyron michnoi, and Artemisia frigida. In addition, calculating relative dry weight of each species can help in identifying best periods for grazing practices during the grassland community is restored.%对处于退化恢复演替过程中的羊草草原群落,通过样方法获得其地上部分干、鲜生物量,研究羊草草原的围封动态并对围栏封育效果进行评价.结果表明,羊草群落干鲜比值呈现在波动中略有上升的趋势,波动主要有两个原因:一是降水量的变化;二是演替不同阶段物种组成的差异.各主要科的干鲜比值以禾本科最高,其次为菊科和豆科,各主要科干鲜比值的排序可以解释群落干鲜比值的变化趋势.各物种干鲜比值的变幅较大(锦鸡儿最高,瓦松最低,变幅为0.45),但起主要作用的是羊草、冰草和冷蒿.计算物种的相对干重可以确定草原恢复过程中的最佳放牧时期.
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