黄河三角洲不同林分类型对土壤水分物理特性的影响

Effects of different forest stands on soil water physical properties of saline-alkali land in the Yellow River Delta

【目的】探讨黄河三角洲不同林分类型对盐碱地土壤水分物理性质的影响,以期为盐碱地植被恢复和树种选择提供理论依据。【方法】以未造林盐碱空地为对照,选择盐碱地3种林分类型(白蜡、柳树、杜梨)为对象,运用野外取样与室内分析相结合的方法,对各样地0~60 cm不同土层深度的土壤容重、孔隙度、持水贮水能力以及渗透性等指标进行了分析。【结果】与未造林空地相比,白蜡、柳树、杜梨3种林分样地的0~60 cm土层平均土壤含盐量、容重分别降低了63.33%、59.46%、50.37%和7.59%、5.70%、3.16%,而平均总孔隙度和毛管孔隙度分别提高了10.64%、6.10%、4.22%和2.56%、9.52%、5.36%,且中上层(0~40 cm)明显优于下层(40~60 cm);不同林分类型在降低土壤容重、提高土壤孔隙度方面以白蜡林最佳,杜梨林最弱;土壤持水、贮水性能在不同林分类型和各土层间虽存在一定差异,但均优于空地,其中白蜡、柳树、杜梨3种林分类型的0~60 cm土壤平均饱和贮水量分别为空地的1.11、1.06和1.04倍,与空地差异显著(P <0.05);3种林分类型的土壤入渗过程均能用回归方程进行高精度拟合,不同林分类型的土壤初渗速率、稳渗速率及平均入渗速率大小均表现为白蜡林>柳树林>杜梨林>空地,且与空地差异显著(P <0.05)。【结论】在黄河三角洲区营造不同类型人工林均有利于改善土壤水分物理状况,提升盐碱地土壤质量,今后在该区植被恢复过程中可考虑采用白蜡树种造林。

【Objective】The effects of different forest types on the soil water physical properties of saline-alkali soils in the Yellow River Delta were studied, which provided a theoretical basis for the restoration of vegetation and the trees selection in saline-alkali soils.【Method】The soil bulk density, porosity, water holding capacity, water storage capacity and permeability of different soil layers in different depths of 0-60 cm in saline-alkali land were analyzed by using field sampling and indoor analysis methods, taking the nonafforestation saline-alkali land as the control and three forest types(Fraxinus velutina、Salix psammophila、Pyrus betulifolia) in salinealkali land as the object of study.【Result】Compared with bare land, the average soil salinity content and bulk density of the Fraxinus velutina、Salix psammophila and Pyrus betulifolia decreased by 63.33%, 59.46%, 50.37% and 7.59%, 5.70%, 3.16%%, respectively, while the average total porosity and capillary porosity increased by 10.64%, 6.10%, 4.22% and 2.56%, 9.52%, 5.36%. And the index of upper and middle soil layers(0-40 cm) is better than that of lower soil layers(40-60 cm). The improvement effect of each forest on soil was slightly different, among which Fraxinus velutina forest had the best improvement effect, while improvement effect of Pyrus betulaefolia forest was the worst. Soil water holding capacity and water storage performance differed in different forest stands and soil layers, but they were superior to bare land. The average saturated water storage of 0-60 cm soils in three forest types was 1.11 times, 1.06 times and 1.04 times compared with bare land, both were significantly different from bare land(P < 0.05). Soil infiltration process of three forest types can be accurately fitted by regression equation, and the difference with bare land was significant(P < 0.05). The three infiltration rates were all expressed in the order: Fraxinus velutina forest > willow forest > Pyrus betulaefolia forest > bare land.【Conclusion】In summary, plantation of different types of plantations in the Yellow River Delta is beneficial to improving soil moisture-physical condition and improving soil quality in saline-alkali land. In the future, plantation with Fraxinus velutina species can be considered in the process of vegetation restoration in this area.