桑树/苜蓿间作对根际土壤酶活性和微生物群落多样性的影响

Effects of Intercropping between Mulberry and Alfalfa on Soil Enzyme Activities and Microbial Community Diversity in Rhizophere

以桑树(Morus alba)/苜蓿(Medicago sativa)间作系统为研究对象,探讨间作种植模式对根际土壤酶活性及土壤微生物群落功能多样性的影响。结果表明:间作苜蓿的蔗糖酶和过氧化氢酶活性分别比单作苜蓿提高了30.0%和21.4%,达显著差异水平;而间作桑树则相反,分别比单作桑树降低了23.8%和2.6%,达显著差异水平;间作桑树和间作苜蓿的根际土壤酸性磷酸酶活性分别比单作提高了23.0%和28.9%,而脲酶活性则分别降低了52.4%和44.3%,二者差异显著。在桑树/苜蓿间作体系下,间作桑树的表征土壤微生物代谢活性强弱平均颜色变化率、多样性指数、均匀度指数和优势度指数均显著高于单作桑树,而间作苜蓿均低于单作苜蓿,达显著差异水平。主成分分析表明,间作种植模式改变了作物根际土壤微生物群落的主要碳源类型,使苜蓿的主要碳源变为氨基酸、聚合物和其他化合物,与单作之间具有显著差异。表明桑树/苜蓿间作提高了桑树根际土壤微生物群落的多样性,改变了苜蓿根际土壤微生物群落利用主要碳源的类型。

The effects of intercropping between mulberry and alfalfa on the enzyme activities and functional diversities of rhizophere soil microbial community were investigated comparing with mulberry monoculture and alfalfa monoculture in the field experiment. The results showed that the invertase and peroxidase ac- tivities of intercropping alfalfa increased 30.0% and 21.4% compared to monoculture alfalfa, respectively; the acid phosphatase activities of intercropping mulberry and intercropping alfalfa raised 23.0% and 28.9% compared to monocultures, respectively. The activities of the enzymes were significant differences between monoculture and intercropping. In mulberry and alfalfa intercropping system, average well color develop- ment （AWCD） symbolized the metabolic activities of soil microbes. Shanon index, Simpson index, and McIntosh index of intercropping mulberry were higher than that of monoculture, while theses indexes in intercropping alfalfa were lower than that of monoculture. Principal component analysis （PCA） showed that the main carbon source types of intercropping and monoculture were different, the main carbon sources of intercropping alfalfa changed into amino acid, polymers and miscellaneous. The research indica- ted that the intercropping system enhanced the diversity of rhizophere soil microbial community of mul- berry, and changed the main carbon source types of rhizophere soil microbial community of alfalfa. The effects of intercropping patterns on soil enzyme activities were different.