在靖远县盐碱地土壤上研究了不同改良措施对土壤微生物数量的影响。结果表明，秸秆还田、盐碱地调节剂、生物有机肥、微生物菌剂均能够有效地增加土壤微生物数量和总碳源利用率。在0～20 cm土层，随玉米生长期推移，生物有机肥(2 400 kg/hm2基施)对细菌和放线菌数量影响较大，秸秆还田(玉米秸秆15 000 kg/hm2还田)对真菌数量影响最显著；在20～40 cm土层，生物有机肥对细菌影响最大，秸秆还田对真菌影响最大。不同土层细菌、真菌和放线菌数量均随玉米生育期推移而降低。0～20 cm土壤微生物培养7 d后对总碳源利用由大到小为秸秆还田、生物有机肥、常规施肥、微生物菌剂、盐碱地调节剂、不施肥，AWCD值介于0.22～1.28；20～40 cm土壤微生物培养7 d后对总碳源利用由大到小为秸秆还田、常规施肥、盐碱地调节剂、生物有机肥、微生物菌剂、不施肥，AWCD值介于0.16～0.96。

The effects of different ameliorating measures on soil microorganism quantity in saline-alkali soil of Jingyuan County were studied. The results showed that straw returning(CS)， saline-alkali soil conditioner (Ra)， bio-organic fertilizer(BF)and microbial inoculants(EM) could effectively increase the number of soil microorganisms and the utilization rate of total carbon sources. In 0～20 cm soil layer， with the growth of corn， the number of bacteria and actinomycetes was significantly affected by BF(2 400 kg/hm2 basal fertilizer)， and the number of fungi was significantly affected by CS(corn straw returning 15 000 kg/hm2). In the soil layer of 20 ~ 40 cm， the effect of BF on bacteria was the greatest， and the effect of CS on fungi was the greatest. The number of bacteria， fungi and actinomycetes in different soil layers decreased with the growth period of corn. After 7 days of microbial culture in 0～20 cm soil， the utilization of total carbon sources ranged from large to small， including CS， BF， conventional fertilization(CF)， EM ，Ra and no fertilization， with AWCD value ranging from 0.22 to 1.28. After 7 days of microbial culture in 20～40 cm soil， the utilization of total carbon sources ranged from large to small， including CS， CF， Ra， BF， EM and no fertilization， and the AWCD value ranged from 0.16 to 0.96.

S156.4；S513