不同强度放牧后沙质草场土壤微生物的分布特征

Characteristic of Microbe Numbers in Sandy Grassland under Different Grazing Intensities after Years of Post-grazing Restoration

本文通过对科尔沁沙质草场不同强度放牧后围栏封育过程中表层(0-5cm)和亚表层(5-15cm)土壤微生物及土壤因子的研究表明:不同放牧强度围栏内,土壤微生物总数表现出:轻牧区>中牧区>对照区>重牧区>自由放牧区,11年的围栏封育不能使不同放牧强度下的沙质草场恢复到相同水平;亚表层土壤的细菌、真菌和放线菌数量、pH、电导率和含水量均大于表层土壤。轻牧和中牧有利于微生物各类群的生长繁殖,过度放牧会抑制微生物的活动,一直自由放牧则会严重破坏沙质草场表层土壤,使其微生物数量和土壤含水量减少,土壤碱性增强。

The research was about the characteristics of microbe numbers and soil factors under different grazing inten- sities at two layers after years of post - grazing restoration in Horqin Sand Land. The results showed that the total microbe numbers were different ： light - grazing plot （LG） 〉 moderate - grazing plot （MG） 〉 non - grazing plot （CK） 〉 heavy- grazing plot （HG） 〉 free -grazing plot （FG） ; they were still not at the same level after 11 years of fencing restoration in the areas under different grazing intensities. The numbers of microbe, including bacteria, fungi, and actinomyces, and pH, electrical conductance, soil miosture at the lower soil layer （5 - 15cm） were higher than the upper layer （0 -Scm）. Light -grazing and moderate -grazing helped microbes be eugonic, while heavy - grazing decreased microbe activity ; and free - grazing could destroy the upper soil layer badly, and also change microbe numbers, soil moistuere and pH, so free -grzaing played a detrimental role in the restoration of sandy grassland.