Soil microbial numbers in four grasslands recovered by different control measures such as shallow ploughing, harrowing, sowing Leymus chinensis and enclosed &- grazing, were measured through spread-plate-technique. The result showed that soil microbial numbers of the grassland recovered were significantly more than those of controlled grassland unrecovered. In the 0~-10 cm soil layer, soil microbial numbers of four grasslands recovered were gradually decreased in order of shallow ploughing, harrowing, sowing Leymus chinensis and enclosed &- grazing. Compared to controlled grassland unrecovered, the bacteria of four grasslands recovered increased by 91. 95%, 89. 66%, 97. 36% and 73. 56%, the fungi increased by 53.06%, 50. 34%, 50. 34% and 23. 81%, the actinomycetes increased by 41. 27%, 38. 89%, 24.47% and 22. 36%, respectively. In the 10~30 cm soil layer, the bacteria and actinomycetes of four grasslands recovered were gradually decreased in order of shallow ploughing, harrowing, sowing Leymus chinensis and enclosed &- grazing respectively. Compared to controlled grassland unrecovered, the bacteria increased by 43. 59%, 43.59%, 41.03% and 33. 33%, the actinomycetes increased by 34. 19%, 31.15%, 29. 14% and 5. 39% , respectively. The fungi of four grasslands recovered in the 10-30 cm soil layer were gradually decreased in order of enclosed & grazing, sowing Leymus chinensis, shallow ploughing and harrowing. Compared to controlled grassland unrecovered, the bacteria of four grassland recovered in the 10 ~30 cm layer increased by 221. 74%, 191. 30%, 162. 86% and 161. 43%. After taking different control measures, the change of bacteria, actinomycetes, and fungi in the grassland soil were not identical. In the 0~10 cm layer, the change of bacteria was the fastest, and the change of fungi was faster than that of actinomycetes, but in the 10~30 cm layer ,the change of fungi was the fastest, and the change of bacteria was faster than that of actinomycetes. For soil microbial, there was significant difference between four grasslands recovered and controlled grassland unrecovered.%利用纯培养技术,对退化草原四项不同治理措施(浅耕翻、耙地、播种羊草、围栏封育)处理后的土壤微生物进行研究.结果表明,四项治理措施中,各类群土壤微生物均显著高于对照区.0～10 cm土层,微生物各类群的数量均依次为浅耕翻＞耙地＞播种羊草＞围栏封育＞对照；四项治理措施细菌数量依次比对照区增高了91.95％、89.66、87.36％和73.56％；真菌数量增高了53.06％、50.34％、50.34％和23.81％；放线菌数量增高了41.27％、38.89％、24.47％和22.63％.10～30 cm土层,细菌和放线菌的数量均依次为浅耕翻＞耙地＞播种羊草＞围栏封育＞对照；四项治理措施细菌数量依次比对照区增高了43.59％、43.59％、41.03％和33.33％;放线菌数量分别比对照区增高了34.19％、31.15％、29.74％和5.39％；而该土层真菌数最则依次为围栏封育＞播种羊草＞浅耕翻＞耙地＞对照,四项治理措施分别比对照增高了221.74％、191.30％、162.86％和161.43％.采取不同治理措施后,微生物各类群的数量增高幅度各不相同,其中0～l0cm土层细菌数量增高幅度最高,真菌次之,放线菌最低.而l0～30cm土层真菌数最增高幅度最高,细菌次之,放线菌最低.四项治理措施土壤微生物与对照均有显著性差异.
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