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以放牧为对照,应用PLFA法分析研究了放牧、连续6年围封及围封内连续6年施肥后高寒草甸土壤微生物群落结构的变化.结果表明:围封和围封内施肥对不同土层各菌群和微生物总量均有显著影响,其对0～10cm土层微生物的影响大于10～20cm土层,不同土层的PLFA种类发生显著变化.围封和围封内施肥处理不同土层的革兰氏阴性菌(G-)含量均低于放牧;放牧0～10cm土层中细菌、真菌、革兰氏阳性菌(G+)、微生物总量大于围封和围封内施肥处理,但其放线菌生物量均低于围封和围封内施肥处理;在10～20cm土层中,各样地土壤中的G+无显著差异,围封土壤中的细菌、真菌、放线菌、微生物总量显著高于放牧,而围封内施肥后各菌群生物量及微生物总量明显下降.围封和围封内施肥不同土层的细菌/真菌均高于放牧;一般饱和脂肪酸/单烯不饱和脂肪酸(SAT/MONO)和革兰氏阳性菌/革兰氏阴性菌(G+/G-),围封处理均低于放牧,围封内施肥处理均高于放牧.连续围封和围封内施肥后降低了土壤微生物活性和土壤生态系统的稳定性.
Using grazing as the control, the changes of soil microbial community structure in alpine meadow after six years of grazing and enclosure for 6 consecutive years were studied by PLFA method.The results showed that: And the total amount of microorganisms in the soil layers were significantly affected. The effect on soil microorganisms in the 0 ~ 10cm soil layer was greater than that in the soil layer of 10 ~ 20cm soil layer. PLFA species changed significantly in different soil layers. Gram-negative bacteria (G-) content in grazing layer was lower than that in grazing. Bacteria, fungi and Gram-positive bacteria (G + However, the biomass of actinomycetes was lower than that of enclosed and enclosed fertilization treatments. There was no significant difference in soil G + contents in 10-20 cm soil layers. The bacteria, fungi and actinomycetes , The total amount of microorganisms was significantly higher than that of grazing, while the biomass and total amount of microorganisms decreased significantly after the fertilization in the enclosure.The bacteria / Monounsaturated fatty acids (SAT / MONO) and Gram-positive bacteria / Gram-negative (G + / G-), the processing enclosure are lower than grazing, they were higher than the inner enclosure fertilization Grazing continuous enclosure after fertilization and soil microbial activity, and reduces the stability of the enclosed soil ecosystem.