Abstract: [Objective] The purpose of this project is to study the variation of soil bulk density in the horizontal and vertical directions and the influence of the gravel content on the determination results of bulk density in the hope of promoting the standardization of soil analysis and soil resource management.[Method] Based on field soil survey,56 soil profiles were dug in grassland of the Ili Valley.Soils were sampled by using core method at uniformly set soil layers,and each layer was repeatedly sampled five times.Gravel content was measured in lab when it existed at a certain soil layer.The coefficient of variation (CV) was used to quantitatively express lateral variation of soil bulk density.[Result] The mean CV values of soil bulk densities measured from five samples for all soil layers were lower than 8;.Gravel could improve soil bulk density by about 16;.Soil bulk densities of varied soil layers at vertical direction were significantly different,and bulk density increased along with increasing soil depth.[Conclusion] Soil layer should be rationally classified when studying bulk density of soil profile in grassland.In view of the fact that highly stony soils existed in grassland of Xinjiang,we suggest that the relevant standard for measuring bulk density should be modified.

摘要： [目的]研究剖面尺度水平方向和垂直方向土壤容重的变异性,砾石含量对容重测定结果的影响,促进土壤分析和土壤资源管理的标准化.[方法]基于野外土壤调查,在伊犁河谷草地挖掘了56个土壤剖面,按照统一设定的深度范围,用环刀法采集土样,每层土壤重复5次.当有砾石时,测定该土层的砾石含量.用变异系数定量表征水平方向土壤容重的变异性.[结果]每层土壤5次重复容重变异系数的平均值均在8;以内,存在砾石会使土壤容重偏高约16;.垂直方向不同深度范围土壤容重差异显著,容重随深度增加而升高.[结论]研究草地土壤剖面的容重时,土层深度的划分要合理.需要针对新疆草地土壤砾石含量较高的状况,修订容重测定的相关标准方法.