Effect of rainfall among years and grazing disturbance on growth rate of Nostoc commune

Nostoc commune is a nitrogenfixing blue algae with reversibly characteristic and it plays an important role in the nitrogen cycle of the natural grassland. A simulation experiment was conducted to determine the effects of rainfall and grazing intensity on the growth rate of N. commune in this study. The results of this study indicated that moderate grazing benefited the growth of N. commune, and its growth rate was three times and four times at early and late growth stage of nograzing, respectively, and the lowest N. commune growth rate was observed in the nograzing treatment. Rainfall showed different effects on the early growth rate and the late growth rate of N. commune, indicating that the high rainfall significantly increased the early growth rate, and the early growth rate in highrainfall treatment was fourteen times that of low rainfall, and moderaterainfall significantly increased the late growth rate. The highest early growth rate of N. commune was presented in the treatment with moderate grazing and highrainfall and the highest late growth rate of N. commune was presented in the treatment with moderate grazing and averagerainfall.