北京西山地区人工林土壤水分特性的研究

通过实测得出土壤水分特征曲线和土壤水分常数,并对北京西山地区不同立地条件下的土壤水分特性进行分析.结果表明,在中、低吸力段(＜1 5 MPa)土壤水吸力与土壤含水量之间存在显著的函数关系,经验方程:θ=ΑS-B对该地区的土壤水分特征曲线有良好的模拟性,土壤的有效水上限(田间持水量)为0.03 MPa 土壤水吸力所对应的土壤湿度,易效水与难效水的吸力界点以0.3 MPa 为宜,土壤的持水性和供水性较低,混交林水分特性优于纯林,同一立地条件下,底层土优于表层土.

Soil water characteristics of plantations in the west Mountains of Beijing

The soil water characteristics of different site conditions in the West Mountains of Beijing were analyzed by measuring the soil water characteristic curves and the soil water constants in the plots. The results showed that there was a high power function correlation between the soil moisture content and soil suction during the low and medium soil suction(<1 5 MPa) and the empirical equation θ=ΑS -B could well simulate the water characteristic curve. The upper limit of available water (field moisture capacity) was the soil moisture content corresponding to the suction of 0 03 MPa and it was suitable to take 0 3 MPa as the boundary point of suction for readily available water and resistantly available water. Capacity of soil water retention and supply was low. The soil moisture characteristics of the mixed forest stands were better than those of the pure forest stands and those of the subsoil were better than the topsoil in the identical site conditions.