典型黑土区坡耕地土壤微生物群落数量的空间分布研究

Spatial Distribution of Soil Microbial Community on Sloping Farmlands in Typical Black Soil Region

选取土壤侵蚀较严重的黑龙江省宾县宾州河流域为研究区,通过采集流域上、中和下游6个典型坡面的坡上、坡中和坡下部土壤样品,分析了坡耕地土壤微生物群落数量在流域和坡面尺度上的分布规律,并比较了土壤微生物群落数量空间分布与土壤侵蚀空间分布的关系。结果表明,在流域尺度上,土壤微生物总数量和细菌数量均表现为:下游>中游>上游;土壤真菌数量表现为:上游>下游>中游;土壤放线菌数量表现为中游最大,而上游和下游数量相当。在坡面尺度上,土壤微生物总数量和细菌数量均呈现:坡中部<坡上部<坡下部,土壤真菌数量呈现:坡下部<坡中部<坡上部,土壤放线菌数量呈现:坡中部<坡下部<坡上部。研究表明,流域土壤微生物总数量和土壤细菌数量的空间分布皆与侵蚀—沉积速率的空间分布相对应,反映出侵蚀—沉积速率是影响该流域土壤微生物群落数量的主要因素。

Soil samples from different slope positions of the upper, middle and down stream of Binzhou river basin were collected to analyze the spatial distribution of soil microbial communities, as well as to compare the relationship of spatial distribution between soil microbial communities and soil erosion. The results showed that the number of soil microbial communities and bacteria ranked as downstream〉mid-stream〉 upper-stream at the watershed scale, the number of fungi ranked as upper-stream〉downstream〉mid-stream at the watershed scale, and the number of actinomycetes was the highest alue in the middle of stream. The number of soil microbial communities and bacteria in different slope positions followed the order： down-slope upper-slope〉mid-slope, the number of fungi in different slope positions followed the order： upper-slope〉 mid-slope〉down-slope, and the number of actinomycetes in different slope positions followed the order： up- per-slope〉down-slope〉mid-slope. The results also indicated the spatial distribution of soil bacteria and microbial community corresponds with the spatial distribution of the rate of soil erosion-deposition, which demonstrated that soil erosion--deposition rate was the key factor for governing the spatial distribution of soil microbial community and bacteria in Binzhou river basin.