不同土地利用方式对微生物特性及土壤理化性质的影响

研究三江地区土壤中3大类微生物数量在春、秋两季的季节性动态变化,及可培养细菌在不同土壤中的分布与种属鉴定.研究结果表明,原生态土壤的优势细菌种类及分离出的细菌种类最多,其次为农作物种植区土壤,退耕还草土壤分离出的细菌种类最少,细菌种类较为单一,但优势菌种所占比例大.同时,不同土壤类型有其特有的菌属.通过对不同耕作下的土壤、退耕还草土壤、原生态土壤理化性状进行测定和分析,说明三江地区不同土地利用方式对土壤肥力的影响.结果表明:随着开垦时间的增加,土壤的理化性质发生渐变.物理性质方面,孔隙度和田间持水量逐年减少;化学性质方面,有机质和其他养分随开垦时间的增加而逐年降低,退耕还草后土壤性质有所恢复,原生态的土壤肥力最强.说明退耕还草有利于改善当地的土壤理化状况.

The Effect on Microbial Characters and Soil Physicochemical Properties Under Different Land Utilization Patterns

The report studied three large kinds of microbial biomass from the soil of the three-river area,seasonal dynamic variations between spring and autumn,distribution and generic identification of cultivable bacteria from different soil.During the investigation,primary soil had more dominant bacterial species,which could be separated move from.Crop belts had less,and returned farmland to grassland the least,which had monotonous bacterial species,with a large ratio of dominant bacterium.Meanwhile,soil of different types had its own genera of bacterium. Determinations and analyses to the physicochemical properties of soil from different utilized land,returned farmland to grassland and primary,explain the effect on soil fertility under different land use patterns of the three-river area.The result showed that physicochemical properties gradually changed with the time increase of cultivation.From physical properties,porosity and field capacity decreased by years;from chemical properties,organic matter and other nutrient reduced with the time of increase cultivation.Soil properties of returned farmland to grassland could restore to some certain degrees.Fertility of primary soil was the best,showed that returned farmland to grassland could improve the physicochemical properties of local soil.