黄土高原草地土壤物理性质初步研究

Research on Soil Physical Properties of Grass Land in the Loess Plateau

黄土高原草地土壤的颗粒组成受草地盖度、产量的影响较小,主要受土壤地带性分布的影响。草地土壤的容重、总孔隙度受草地植物的盖度、产量的影响。盖度、产量低时,土壤容重≥1.20g/cm^3,总孔隙度在55.0%左右;盖度、产量高时,土壤容重≤1.20g/cm^3,总孔隙度≥60.0%。草地土壤的三相比:植物盖度、产量低时为1∶0.10～0.19∶0.60～0.90,反之则为1∶0.33～0.75∶1.15～1.76。土壤物理性质与草地枯枝落叶层,土壤有机质含量有密切关系。草地土壤的物理性质和植物根系密度是改善土壤水力学特征、强化土壤抗冲性、土壤入渗性能和斜坡稳定性增值的关键所在。

The soil particle composition of grassland is affected slightly by the cover-degree and yield of grass in theLoess Plateau. It is mainly affected by the distribution of soil zonality. The volume weighet and total porosity ofgrassland are affected by the cover-degree and yield of grass. When the cover-degree and yield are low , the soilvolume weight is greater than or equal to 1. 20g/cm^3 and the soil total porosity is around 55%; with the increase inthem,the soil volume weight will become less than or equal to 1. 20g/cm^3 and the soil total porosity become greaterthan or equal to 60%. When the cover-degree and yield are low,three phase ratio of solid, liquid and gas for grass-land is 1 : 0. 10～0. 19: 0. 60～0. 90; conversely,that raito become 1: 0. 33～0. 75: 1. 15～1. 76. The soil physicalproperties of grassland are correlated with litter layer and content of soil organic matter. The soil physical proper-ties and the density of root system are keys to improve characteristics of soil hydraulics,to strength soil anti-scau-rability and infiltraion,and to increase slope stability.