北京西山酸枣灌木林对土壤物理性质的影响

Effects of Ziziphus jujube on Soil Physical Properties in West Mountains of Beijing

采用野外调查与室内分析相结合的方法，研究了北京西山酸枣林对土壤物理性质的影响。结果表明：①酸枣林地中92．43％的根系分布在0—30em土层中。②0～15cm、15～30cm、〉30cm土层的土壤容重分别为1．03g,／cm3、1．22g,／cm3和1．56g／cm3，土壤容重与根系量呈负指数相关关系。③土壤孔隙度变化趋势与根系分布一致，土壤总孔隙度、毛管孔隙度均与土壤容重呈正指数曲线关系，平均土壤总孔隙度、毛管孔隙度分别为31．49％、26．49％。④土壤含水量变化规律为5、6月份较低，7～10月份较高，其中6月份最低、7月份最高，分别为5．20％、15．55％；各土层土壤含水量变化趋势与根系分布情况一致。⑤土壤团聚体总体变化趋势为：2．0～1．0mm／l粒径的最多，占78．58％；〉2．0mm粒径的次之，为18．63％；〈0．05mm粒径的最少，只有2．79％；团聚体结构含量变化与根量变化趋势相似。⑥土壤初渗速率为9．09mm／min，稳渗速率为0．88mm／min。

The effects of Ziziphus jujube on soil physical properties in West Mountains of Beijing have been studied by use of the method of field investigation and indoor analysis. The results show, （ 1 ） In forest land of Ziziphus ju- jube, there are 92.43% of root system distribute in 0 ～30 cm soil layer. （2） The soil bulk density in 0 - 15 cm, 15 - 30 cm and 〉 30 cm soil layer is 1.03 g/cm3, 1.22 g/cm3 and 1.56 g/cm3 separately. The relation between soil bulk density and root amount is negative exponent correlation. （3） The change of soil porosity is consistent with the distribution of root system. There is positive exponential curve relation among soil total porosity, capillary porosity and soil bulk density. The average soil total porosity and capillary porosity is 31.49% and 26.49% sepa- rately. （4） The soil water content is lower in May and June, and it is higher from July to October, with 5.20% for June and 15.55% for July. The changing tendency of soil water content in each soil layer is same with the distribu- tion of root system. （5） The total change tendency of soil aggregate is that the particle size from 2.0 mm to 1.0 mm takes up 78.58%, the particle size bigger than 2.0 mm takes up 18.63% and the particle size less than 0. 05 mm takes up 2. 798%. The content of aggregate structure changes with the root amount. （6） The initial infiltration is 9. 09 mm/min and the steady infiltration is 0. 88 mm/min.