季节性放牧利用对典型草原群落生产力的影响

Effect of Seasonal Grazing Use on Productivity of Grassland Community

研究了内蒙古典型草原区生长季内放牧时间及放牧方式对羊草（Leymus chinensis）＋糙隐子草（Cleistogenes squarrosa）＋克氏针茅（Stipa krylovii）群落的影响,结果表明：（1）对照群落地上生物量为单峰曲线且与羊草及糙隐子草地上现存量显著相关;（2）以群落留茬高度6cm确定各个季节终牧时间,T3处理的草地利用率最高;除9月生长季末期之外,各个季节放牧周期内群落放牧间期的净积累量能够补偿放牧处理期羊群的采食量;（3）放牧间期,群落净增长速率高于对照处理,即放牧间期植物群落存在普遍的补偿性生长机制;（4）放牧处理降低草地群落地下根系的积累,尤其表现在降低0～30cm土壤层的根系积累量.

In growing season, the effect of seasonal grazing use on Leymus chinensis ＋Cleistogenes squarrosa ＋ Stipa krylovii community in typical grassland of semiarid area of Inner Mongolia was stud- ied. The results showed that： （1） During the growing season, community biomass on the ground showed a single--peak curve, and was correlated to the production of standing crop of Leymus chinensis and Cleis- togenes squarrosa. （2） Grazing was stopped when the community stubble height was 6cm, the grassland u- tilization rate in T3 treatment was the highest. In addition to the end of the growing season in September, the accumulation of net production in the period between two grazing treatment time can compensate the intaking biomass during grazing treatment period by the sheep. （3） During no grazing period, community net growth rate was higher than the CK, a widespread compensatory growth mechanism existed during no grazing period. （4） Grazing reduced root accumulation, especially in roots in 0 to 30 cm soil layer.