外来杂草反枝苋对大豆根际土壤微生物碳源利用和土壤理化性质的影响

为探讨外来杂草反枝苋对大豆根际土壤微生物碳源利用和土壤理化性质的影响,比较分析了三种不同物种组成的群落,即单种大豆、单种反枝苋、大豆与反枝苋混种的群落中,反枝苋和大豆根际土壤微生物碳源利用情况和土壤理化性质的变化。结果表明:在大豆开花结荚期,混种大豆根际土壤微生物比单种大豆多利用了3种碳源,混种反枝苋与单种反枝苋相比利用的碳源种类数相同;在大豆鼓粒期,混种大豆比单种大豆少利用了9种碳源,混种反枝苋比单种反枝苋多利用了6种碳源;在大豆成熟期,混种大豆利用的碳源种类总数与单种相同,混种反枝苋比单种反枝苋多利用了4种碳源;在土壤理化性质方面,与单种大豆相比,混种大豆根际土壤的有效氮含量和温度均降低,土壤的有机质含量、pH值、含水量和全氮含量升高,且都在大豆鼓粒期差别最大。说明外来杂草反枝苋的入侵改变了大豆根际土壤的理化性质,影响了其根际土壤微生物碳源利用的能力,进而抑制了大豆的生长。

Effects of Invasive Weed-Amaranthus retroflexus on the Carbon Source Utilization of Glycine max Rhizosphere Microbes and Soil Chemical and Physical Properties

In order to study the effects of Amaranthus retroflexus on the microbial carbon source utilization and the chemical and physical properties of Glycine max rhizosphere soil in the farmland,the three type communities,Glycine max monoculture,Amaramthus retroflexus monoculture,and Glycine max and Amaramthus retroflexus mixture were established in the experiment.The results showed that on the stage of flowering and pods formation,compared with the monoculture Glycine max,additional three carbon sources were used in mixture Glycine max.The number of carbon sources was the same in the mixture ones compared with the monoculture Amaramthus retroflexus.On the stage of seed-filling,compared with the monoculture Glycine max,nine carbon sources were unused in mixture Glycine max,and there were six carbon sources were used in the mixture Amaramthus retroflexus more than the monoculture one.On the stage of maturity,compared with the monoculture Glycine max,the number of carbon sources was the same in the mixture ones,and there were four more carbon sources used in the mixture Amaramthus retroflexus than the monoculture ones.Compared with the monoculture Glycine max,the mixture Glycine max rhizosphere soil contained lower available nitrogen and temperature but higher organic matter,pH value,water content,and total nitrogen and this differences were significant in the seed filling period of Glycine max.In conclusion,the microbial carbon source utilization ability of Glycine max rhizosphere soil was decreased by the invasion of Amaramthus retroflexus,and the chemical and physical properties of Glycine max rhizosphere soil were changed,so as to affect the growth of Glycine max.