桑树-大豆间作对盐碱土碳代谢微生物多样性的影响

针对桑树-大豆间作可缓解盐碱土危害的特点,利用BiologTM技术研究了桑树-大豆间作对盐碱土作物根际碳代谢微生物多样性的影响.结果表明:表征土壤微生物代谢活性的平均颜色变化率(AWCD)在桑树-大豆间作下明显高于桑树单作和大豆单作,其中间作大豆的AWCD最高,单作桑树最低.桑树-大豆间作的土壤微生物均匀度指数高于单作,而土壤微生物的多样性指数和优势度指数在间作和单作之间差异不显著,说明桑树-大豆间作改变了盐碱土根际微生物群落结构组成,提高了根际微生物群落多样性.主成分分析表明,桑树-大豆间作和单作下土壤微生物的碳源利用模式出现分异,主要碳源为糖类、羧酸和聚合物类物质等.盐碱土pH和盐度是制约微生物群落多样性的主要因素,间作有效降低了土壤pH和盐度,促进了土壤微生物群落多样性的提高.

Effects of mulberry-soybean intercropping on carbon-metabolic microbial diversity in saline-alkaline soil

Aiming at the characteristics that mulberry-soybean intercropping could alleviate the damage of saline-alkaline soil,Biolog technique was adopted to study the effects of this intercropping on the diversity of carbon-metabolic microbial community in the rhizosphere of saline-alkaline soil.Under mulberry-soybean intercropping,the average well color development(AWCD) symbolizing the metabolic activity of soil microbes was obviously higher,as compared with that under mulberry or soybean monocropping,being the lowest under mulberry monocropping.The McIntosh index was also higher under intercropping than under monocropping,but the Shannon index and Simpson index had less difference between intercropping and monocropping,indicating that intercropping changed the composition and enhanced the diversity of the microbial community in the rhizosphere of saline-alkaline soil.Principal component analysis(PCA) showed that the carbon source utilization mode of the soil microbial community differed between intercropping and monocropping,and the main carbon sources were carbohydrate,carboxylic acid,and polymers.Soil pH and salinity were the main factors limiting the diversity of the microbial community in saline-alkaline soil,and intercropping could effectively decrease the soil pH and salinity and promote the improvement of soil microbial community diversity.