不同利用方式对东北羊草草地土壤微生物数量的影响

摘要

Leymus chinensis from steppes of northeast China was selected to investigate contents of soil microbial Population (fungi, bacteria and actinomycetes) under different use patterns. Results are as follows: soil microbial population in fenced grassland is higher than outside fenced. The number of soil microbial population is ordered as fenced mowing grassland >grazing grassland. In three communities (spl?sp2 and sp3) , the number of soil microbial population is ordered as spl>sp3>sp2. In mowing grassland or grazing grassland,the number and distribution of soil microorganisms (fungi, bacteria and actinomycetes) are different among three plant communities. The number of fungi is order as spl>sp3>sp2; the number of bacteria is ordered as sp3>spl>sp2; the number of actinomycete is ordered as spl>sp3>sp2. The number of soil microorganisms greatly varies with soil depth so that the number is much higher within 0~15 cm than that within 15~30 cm (2~4 times). Among microorganisms, the number of bacteria is the highest and the number of fungi is the lowest. There is a closely correlation between spl, sp2 aboveground biomass, and the number of fungi in mowing grassland, but this phenomenon is not observed in grazing grassland. Key words.- Leymus chinensis steppes; Monwing and grazing; Soil microorganisms; Population dynamicsrnAbstract-.Leymus chinensis from steppes of northeast China was selected to investigate contents of soil mi-crobial Population (fungi, bacteria and actinomycetes) under different use patterns. Results are as follows: soil microbial population in fenced grassland is higher than outside fenced. The number of soil mi-crobial population is ordered as fenced mowing grassland >grazing grassland. In three communities (spl?sp2 and sp3) , the number of soil microbial population is ordered as spl>sp3>sp2. In mowing grassland or grazing grassland,the number and distribution of soil microorganisms (fungi, bacteria and actinomycetes) are different among three plant communities. The number of fungi is order as spl>sp3>sp2; the number of bacteria is ordered as sp3>spl>sp2; the number of actinomycete is ordered as spl>sp3>sp2. The number of soil microorganisms greatly varies with soil depth so that the number is much higher within 0~15 cm than that within 15~30 cm (2~4 times). Among microorganisms, the number of bacteria is the highest and the number of fungi is the lowest. There is a closely correlation between spl, sp2 aboveground biomass, and the number of fungi in mowing grassland, but this phenomenon is not observed in grazing grassland.%不同利用方式下(刈割和放牧),比较了羊草(Leymus chinensis)草地土壤微生物多样性(真菌、细菌和放线菌)及群落结构的数量变化.结果表明:土壤微生物的数量在不同利用方式下表现为:刈割草地＞放牧草地,在不同植物群落中表现为:羊草群落＞杂类草群落＞碱茅(Puccinellia distans)群落.无论在刈割还是放牧区,真菌的分布为:羊草群落＞杂类草群落＞碱茅群落；细菌的分布为:杂类草群落＞羊草群落＞碱茅群落;放线菌为:羊草群落＞杂类草群落＞碱茅群落.土壤微生物随土层垂直递减分布,在土层0～15 cm土壤微生物分布最多.3类微生物中,细菌数量最大,放线菌次之,真菌最小.相关性分析表明,只在刈割方式下羊草群落(sp1)和碱茅群落(sp2)土壤的微生物数量与地上生物量显著相关(P＜0.05),其余相关性均不显著.