中文摘要：

以黑河流域灌区不同保护性耕作作为研究对象，研究保护性耕作农田土壤微生物量的季节变化及剖面分布规律，探讨保护性耕作农田土壤有机质、土壤水分和土壤微生物生物量碳、土壤微生物生物量氮的变化规律，分析影响土壤微生物量的因素。结果表明，保护性耕作明显提高农田土壤有机质、微生物量C和微生物量N含量，且均表现为自上层到下层显著递减的规律。黑河流域农田土壤微生物生物量碳含量平均值为158．06mg／kg，变幅为35．04～414．34mg/kg，随季节变化表现为播种期〉休闲期〉收获期，土壤微生物生物量氮含量平均值为24．73mg／kg，变幅为9．47～82．87mg／kg。土壤微生物生物量氮随季节变化也呈现出春秋较高，夏季较低的规律，但季节差异较小。土壤微生物生物量碳对外界环境变化的响应较土壤微生物生物量氮更为敏感，更适宜于作为评价土壤质量快速变化的指标。

英文摘要：

Effect of conservation tillage on soil organic matter （SOM）, soil microbial biomass carbon （MBC）, soil microbial biomass nitrogen （MBN）, crop yield and water use efficiency were explored through field experiments. The results showed that SOM, MBC and MBN under conservation tillage were higher than that under conventional tillage （CT） and decreased with depth. In 0-20cm soil layer in the farmland of Heihe Irrigation District, the mean MBC content was the highest at seeding stage, the lowest at harvesting stage and middle at fallow stage, and the mean value was 158.06 mg/kg （ranged from 35.04 - 414.34 mg/kg）. The mean MBN content was the higher at spring and autumn and lower at summer although has little differences between seasons. The mean SMN content in 0-20 cm soil layer was 24.73 mg/kg （ranged from 9.47 - 82.87 mg/kg）. SMC is a more appropriate index for evaluating rapid changes of soil quality because of the more sensitive reaction to changes of environment compared with that of SMN.