北京西山侧柏林和刺槐林土壤水分研究

Study on the Soil Water Characteristics of R. pseudoacacia and P.orientalis in the West of Beijing

为了解不同人工林树种对土壤的改良情况,探究北京西山地区不同林分下土壤水分状况,通过对原状土样土壤水分特征曲线的拟合,分析刺槐林下和侧柏林土壤的水分状况。研究表明:该区土壤质地较粗,植物利用水分困难,侧柏林下土壤持水性要比刺槐好,侧柏和刺槐对土壤上层和下层改良作用不同;在刺槐林下,上层土壤持水性好于下层;而在侧柏林下,下层土壤持水性则好于上层;在供水性方面,刺槐林较侧柏林好,且同一立地条件下表层优于底层。刺槐林和侧柏林下土壤易效水和难效水的吸力界点都在0.3MPa左右。

In order to understand the improvement of the soil under the different species plantations and to explore the different types of soil moisture conditions in Xishan area of Beijing, original soil samples were taken under R. pseudoacacia and Platycladus. Soil water characteristic curve was measured by using centrifuge de watering experiment. Related parameters were obtained by fitting the curve, then soil moisture conditions were analyzed in the R. pseudoacacia forest and P. orientalis forest. Results showed that the soil texture of this area was coarse and plant utilization of water was really difficulty. Generally, the soil in P. orientalis plantation was more sufficient than the R. pseudoacacia in terms of water retention. And each plant species had different improving effect, and water retention of the upper soil was better than that the lower soil layer. In the R. pseudoacacia forest, the upper soil was stronger than the lower soil in terms of water retention. While in the P. orientalis forest, the upper soil was weaker than the lower in terms of water retention. With regard to soil water supply capacity, R. pseudoacacia was intenser than P. orientalis, and the topsoil was intenser than the subsoil under the same site conditions. Both in the R. pseudoacacia and P. orientalis forest, the boundary point of suction for readily available water and resistantly available water was 0.3 MPa.