Abstract: The experiment was conducted in the degraded rangeland of Artemisia frigida with shortgrasses in 1993 and 1997.The results showed that the belowground biomass decreaded with increase of stocking rate,especially in 1993.In comparison with Leymus chinensis and Stipa grandis steppes.the belowground biomass increased with the trend of distribution in surface soil.The ratio between belowground and aboveground biomass increased with increase of stocking rate,but the ratio between belowground biomass and aboveground net primary productivity(aboveground biomass +intake by sheep)decreascd with increase of stocking rate.

Key words: Inner Mongolia steppe, Stocking rate, Belowground biomass

摘要： 放牧明显地影响着草原植物地下地上生物量及其比例以及光合产物在地上地下部位的分配。结果表明,地下生物量随着放牧率的增大而呈下降趋势,但不同年份的变动较大,地下地上生物量的比例随着放牧率的增大而增大,但地下生物量与地上净初级生产力的比例则随着放牧率的增大而减小,而降水量的大小可改变其变化趋势。在退化冷蒿草原,地上净初级生产力占总生物量(地上＋地下生物量)的比例随着放牧率的增大而增大,而在干旱条件下光合产物对地上部的分配有所减少。与围栏条件下羊草和大针茅草原比较,退化冷蒿草原的根系有表层化的趋势。

关键词: 内蒙古典型草原, 放牧率, 地下生物量