中文摘要：

选择地势平坦相毗邻地块的4种不同土地利用方式（农田,CL;落叶松林地,FL;自然草地,GL;裸地,BL）,利用环刀法测定了土壤容重、田间持水量和饱和持水量,利用吸管法测定了土壤机械组成,利用湿筛法测定了土壤水稳性团聚体,分析了0—200cm剖面内土壤物理性质的分布、变异程度和相关性。研究结果表明：土地利用方式显著影响了表层（0—20cm）的土壤容重、孔隙度和土壤持水量,容重表现为GLCL〉FL〉BL。土地利用方式对剖面土壤颗粒组成的影响表现为GL砂粒含量比较高,BL粉砂含量较高,而FL的粘粒含量较高。粒径〉0.25mm团聚体含量（WAS〉0.25mm）、平均重量直径（MWD）和几何平均直径（GMD）均随剖面深度增加而降低,不同土地利用方式间的差异表现在0—60cm土层,为GL〉FL〉CL〉BL。GL和FL由于根系的作用增加了土壤物理性质的变异程度。土壤颗粒组成对土壤容重、饱和持水量和田间持水量都有显著的影响。研究结果表明,自然草地能够显著改善并恢复土壤的物理性质。

英文摘要：

The distribution of soil were analyzed under 4 different lan physical properties, variability and correlation in 0 200 cm soil profile d use types including cropland（CL）, larch forest（FL）, grassland（GL） and bare land（BL）. Soil bulk density, field water capacity and saturation water capacity were measured by cutting ring method, soil mechanical composition was surveyed by pipette method, and soil water-stable aggregates were determined by wet screening method. The results showed that land use type significantly influenced soil bulk density in the increasing order of GL〈CL〈FL〈BL, and affected soil porosity and soil water capacity in the decreasing order of GL〈CL〈FL〈BL in 0--20 cm soil layer. Sand, silt and clay contents were higher for GL, BL and FL, respectively, in soil profile. The content of 〉0. 25 mm soil aggregates（WAS〉0 .25mm）, mean weight diameter（MWD） and geometry mean diameter（GMD） decreased with the increase of soil depth, and significantly differed among different land use types in 0--60 cm soil layer, which listed in the decreasing order of GL〈FL〉CL〉BL. The roots of grass and larch forest increased the variability of soil physical properties. Soil particle composition significantly influenced soil bulk density, field water capacity and saturation water capacity. Therefore, grassland could improve and restore soil physical properties.