渭北旱塬区不同坡向土地利用类型对土壤性质的影响

Effects of Land Use Types with Different Slope Aspect on Soil Properties in Weibei Highlands

为了研究不同坡向土地利用类型对土壤性质的影响,以渭北旱塬区5种土地利用类型(不同坡向)为研究对象,系统分析该区不同坡向土地利用类型剖面土壤物理、化学和生物性质的差异。结果表明:(1)除土壤pH和土壤颗粒组成外,5种土地利用类型土壤含水量、总孔隙度、有机质、全氮、微生物量碳和氮含量总体随土层加深呈下降趋势,土壤容重则相反。(2)0-30cm土层,阳坡农用地土壤含水量、黏粒含量和pH最高,粉粒和全氮含量最低;人工草地砂粒和全氮含量最高,黏粒含量最低;人工林地土壤总孔隙度、土壤有机质、微生物量碳和氮含量最高,土壤含水量、土壤容重和pH最低;天然草地土壤容重和粉粒含量最高,总孔隙度和砂粒含量最低;退耕地有机质、微生物量碳和氮含量最低。阴坡农用地土壤含水量、粉粒含量和pH最高,黏粒和全氮含量最低;人工草地土壤容重、黏粒和微生物量氮含量最高,土壤总孔隙度、粉粒、砂粒和有机质含量最低;人工林地有机质含量和微生物量碳含量最高;天然草地土壤总孔隙度、砂粒和全氮含量最高,土壤容重和pH最低;退耕地土壤含水量、微生物量碳和氮含量最低。(3)5种土地利用类型中,土壤容重、细黏粒、粗黏粒、细粉粒、粗砂粒、土壤pH和有机质(退耕地除外)表现为阳坡>阴坡,土壤含水量(退耕地和农用地除外)、总孔隙度、粗粉粒、细砂粒、土壤质地粗化度、全氮(人工草地除外)、土壤微生物量碳和氮含量则为阴坡>阳坡。

In order to explore the effects of land use types with different slope aspects on soil properties,five land use types（different slope aspect）in Weibei highlands were selected to analyze the differences of soil physical,chemical and biological properties in different land use types.The results showed that：（1）Soil water content,soil total porosity,soil organic matter content,total nitrogen content,microbial biomass carbon and nitrogen content decreased with the increase of soil depth,soil bulk density was the opposite except soil pH and particle composition in different land use types.（2）In 0-30 cm soil layer,on the sunny slope,soil water content,clay content and pH were the highest,while silt and total nitrogen content were the lowest in farmland;sand and total nitrogen content were the highest,while clay content was the lowest in artificial grassland;soil total porosity,soil organic matter content,microbial biomass carbon and nitrogen content were the highest,while soil water content,soil bulk density and pH were the lowest in artificial forest;soil bulk density and silt content were the highest,while soil total porosity and sand content were the lowest in natural grassland;soil organic matter content,microbial biomass carbon and nitrogen content were the lowest in abandoned farmland.On the shady slope,soil water content,silt content and pH were the highest,while clay content and total nitrogen content were the lowest in farmland;soil bulk density,clay content and microbial biomass nitrogen content were the highest,while soil total porosity,silt,sand and soil organic matter content were the lowest in artificial grassland;soil organic matter content and microbial biomass carbon content were the highest in artificial forest;soil total porosity,sand and total nitrogen content were the highest,while soil bulk density and pH were the lowest in natural grassland;soil water content,microbial biomass carbon and nitrogen content were the lowest in abandoned farmland.（3）Among the 5 types of land use,soil bulk density,fine clay,coarse clay,fine silt,coarse sand,soil pH,soil organic matter content（except abandoned farmland）of sunny slope were higher than those of shady slope.Soil water content（except abandoned farmland and farmland）,soil total porosity,the coarse silt,fine sand,soil texture coarsening degrees,soil total nitrogen content（except artificial grassland）,soil microbial biomass carbon and nitrogen content of shady slope were higher than those of sunny slope.