干旱区绿洲苜蓿地土壤微生物特性及其影响因子

Soil Microbial Properties and Its Impactors in Alfalfa Fields in Arid Land Oasis

研究了干旱区绿洲种植年限不同的3种苜蓿地0-10 cm,10-20 cm土层土壤微生物量碳、微生物量氮、微生物量商、呼吸强度和代谢商的变化特征。结果表明:在耕层0-20 cm范围内,苜蓿种植年限的长短对土壤微生物量碳、土壤微生物量氮含量有影响,相对来说微生物量碳、氮在四年生苜蓿地的含量最高,其次是一年生苜蓿地的。不同种植年限苜蓿地之间土壤微生物量商(qMB)、呼吸强度、代谢商(qCO2)差异显著,相对来说种植年限相差越大,差异越大。相关分析结果表明,土壤理化特性对土壤微生物活性有影响,其中土壤微生物量碳、微生物量氮与土壤有机质、全氮显著正相关,与土壤容重显著负相关。

The contents of soil microbial biomass carbon （MBC）, microbial biomass nitrogen （MBN）, microbial biomass quotient value （qMB）, respiration intensity and microbial metabolic quotient value （qCOe） in three kinds of alfalfa fields at different soil depths （0-10 cm, 10-20 cm） have been preliminarily analyzed through experiments. The results indicat that, in the tilled land with the depth of 0-20 cm, the age for al- falfa growth has effect on the contents of MBC and MBN contained in soil. Comparatively, the field where alfalfa has been planted for four years has maximized content of microbial carbon and nitrogen, followed by one-year cultivated land of alfalfa. The difference is obvious in Microbial biomass quotient value （qMB）, respiration intensity and microbial metabolic quotient value （qCO2） between different fields where alfalfa has been planted, relatively, the longer the years of cultivation is, the larger the difference in Microbial biomass quotient value （qMB） and so on between different fields is. Correlation analysis show that soil physicalchemical property affect the microbial characters, in which soil organic matter and total nitrogen have obvious positive relevance with MBC and MBN while negative relevance with bulk density. Without extraneous fertilizer, the quality of the four years alfalfa field is the best in all the alfalfafields relatively.