Comparison Study On The Response Of Plant Population To Different Grazing Systems In Stipa Breviflora Desert Steppe

A comparison study was conducted on the response of main plant populations, Stipa brevzflora, Cieistogenes songorica and A ilium polyrhizum,to grazing systems in S.brevzflora desert-steppe. It was showed:1 .The tiller densities of the plant were significantly affected by grazing systems. Under continuous grazing the tiller activity of S.brevzflora was enhanced, but that of Cleistogenes songorica and Ailium polyrhizum were reduced.2.The single tiller weight of the same plant was significantly different among grazing systems, besides, there was a significantly correlation with the number of tillers.3 .The aboveground net primary production of the plant was increased when grazing was forbidden for appropriate period. It was more favoring for the recovery and increase of the primary production of the plant populations under rotational grazing than under continuous grazing.4.The yield structure of the plant showed a pyramid shape. There was no significant difference in the ratio of dry weight to fresh weight among the plants.5.The sexual multiplication of the plants was affected by different grazing systems. Under rotational grazing it was more beneficial to survival and growth of seeding than under continuous grazing, but not so effective as under forbidding grazing.6.There are regular dynamics for plant reserves between continuous grazing and rotational grazing, but dynamics are different...