不同植被恢复模式对退化花岗岩红壤渗透性和持水量的影响

Effects of Different Vegetation Restoration Types on Permeability and Water Holding Capacity of Degraded Granite Red Soil

[目的]研究不同植被恢复模式对退化花岗岩红壤渗透性和持水量的影响,为该区水土保持和红壤退化地的精准恢复提供理论依据。[方法]采用野外调查、室内分析和环刀法,以严重退化花岗岩红壤和自然林为对照,对不同植被恢复模式下退化花岗岩红壤的土壤渗透性和持水量进行研究。[结果]不同植被恢复模式和对照样地的土壤渗透性均随土层深度的增加而降低,土壤入渗特征值均表现为:初始入渗率>平均渗透率>稳定入渗率;不同植被恢复模式与对照样地比校,土壤渗透性指标和前30 min土壤渗透总量数值顺序为:自然林>乔灌草>条沟草灌>封禁>低效林改造>全坡面播草>严重退化地;0—40 cm土壤持水量的顺序为:自然林>乔灌草模式>条沟草灌>封禁>低效林改造>全坡面播草>严重退化地。0—5 cm土壤渗透性指标和土壤理化指标的冗余分析表明,土壤有机碳、全氮、全磷、速效磷、全钾、速效钾、pH值、粉粒含量是改善土壤渗透性的因子,而土壤硬度、土壤容重、黏粒和砂砾含量是制约土壤渗透性的因子。[结论]5种植被恢复模式中乔灌草植被恢复模式是改善土壤渗透性和持水量的最佳模式。

[Objective]The effects of different vegetation restoration types on the permeability and water holding capacity of degraded granite red soil were studied in order to provide a theoretical basis for soil and water conservation and accurate restoration of degraded red soil in this area.[Methods]With seriously degraded granite red soil and natural forest(NV)as the control treatment,we determined the soil permeability and soil water holding capacity of degraded granite red soil under different vegetation restoration types using field investigation,laboratory analysis,and the ring knife method.[Results]Soil permeability decreased with increasing soil depth for different vegetation restoration types.The characteristic values of soil infiltration followed the order of initial infiltration rate>average infiltration rate>stable infiltration rate.The soil permeability and the total amount of soil permeability in the first 30 min for the different vegetation types were compared with that of NV.Soil permeability and total soil permeability in the first 30 min followed the order of NV>arbor,shrub,grass(ASG)>grass in irrigation ditches(GGH)>closed canopy(CC)>low-efficiency forest transformation(IFT)>grass sown in the whole slope(FSG)>severely degraded land(HDL).The sequence of saturated water storage in the 0—40 cm soil layer followed the order of NV>ASG>GGH>CC>IFT>FSG>HDL.Redundancy analysis of soil permeability indexes and soil physical and chemical properties from the 0—5 cm soil layer showed that soil hardness,soil bulk density,silt content,and sand content were the factors that restricted soil permeability,and soil organic carbon,total nitrogen,total phosphorus,available phosphorus,total potassium,available potassium,pH value,and clay content were the important factors that could increase soil permeability.[Conclusion]ASG was the best vegetation restoration type to increase soil permeability and water holding capacity.