西藏加乌拉山土壤物理性质垂直地带性特征

Vertical Zonal Characteristics of Soil Physical Properties in Jiawula Mountain,Tibet

以西藏加乌拉山为研究对象,采用野外调查与室内试验的方法,测定加乌拉山山脉南北两侧不同海拔梯度的土壤容重、含水量和孔隙度等8项物理性质,分析不同海拔、不同坡向下各土壤指标的差异性及各指标间的相关性,旨为高原生态建设、区域水土保持工作提供科学理论依据。结果表明,1)不同海拔不同土层土壤物理性质存在一定的差异,不同海拔土壤样品的土壤容重、毛管孔隙度、非毛管孔隙度、总孔隙度、土壤含水量、土壤饱和含水量和土壤毛管持水量的变化范围分别为0.99~1.59 g/cm^(3)、40.85%~67.47%、1.63%~6.76%、42.80%~70.17%、5.71%~20.42%、25.55%~68.55%、25.27%~65.34%。2)在山麓北坡,海拔与容重呈极显著负相关(P<0.01),与土壤饱和含水量、土壤毛管持水量、土壤非毛管孔隙度的相关关系为极显著正相关(P<0.01),土壤容重与其他物理指标呈极显著负相关(P<0.01);在山麓南坡,土壤毛管孔隙度、总孔隙度、土壤毛管持水量与海拔呈显著负相关(P<0.05),总孔隙度、毛管孔隙度、非毛管孔隙度和土壤含水量与土壤容重呈极显著负相关(P<0.01)。3)研究区整体上0~10 cm土层土壤物理性质基本优于10~20 cm和20~30 cm;综合各海拔土壤物理性质表明,山麓北坡随着海拔升高,土壤各项物理指标越好,而南坡则相反。

Taking the Jiawula Mountain in Tibet as the research object,the physical properties of the soils collected from south and north slopes of the mountain with different altitude gradients were measured by field investigation and laboratory test,such as soil bulk density,water content,and porosity.The differences of soil indexes at different altitudes and slope directions,and the correlation among indices were analyzed to provide scientific theoretical basis for plateau ecological construction and regional soil and water conservation.The results show that 1)soil physical properties of different soil layers at different altitudes,The variation ranges of soil bulk density,capillary porosity,non-capillary porosity,total porosity,soil water content,soil saturated water content and soil capillary water holding capacity of soil samples at different altitudes were as follows:0.99-1.59 g/cm^(3),40.85%-67.47%,1.63%-6.76%,42.80%-70.17%,5.71%-20.42%,25.55%-68.55%,25.27%-65.34%.2)On the northern slope,altitude was negatively correlated with bulk density(P<0.01),and positively correlated with soil saturated water content,soil capillary water holding capacity and soil non-capillary porosity(P<0.01).Soil bulk density was negatively correlated with other physical indicators(P<0.01).On the southern slope,soil capillary porosity,total porosity and soil capillary water holding capacity were significantly and negatively correlated with altitude(P<0.05),while total porosity,capillary porosity,non-capillary porosity and soil water content were significantly and negatively correlated with soil bulk density(P<0.01).3)On the whole,the soil physical properties of 0-10 cm soil layer in the study area were better than those of 10-20 cm and 20-30 cm;the physical properties of soil at different altitudes showed that the physical indexes of soil on the northern slope were better with the increase of altitude,while those on the southern slope were opposite.