互助北山国家森公园林下枯落物及土壤水源涵养能力

Water conservation capacity of litter and soil in Huzhu Beishan National Forest Park

【目的】研究青海省互助北山国家森林青扦,白桦,山杨与青扦×白桦×山杨混交林林下枯落物及表层土壤水源涵养功能,以期为本地区水土保持,针阔混交奠定数据与理论基础.【方法】通过建立28 m×28 m树样方,采集枯落物与土壤样品,进行室内浸泡与渗透法测定相关指标.【结果】林下落物层最大持水量表现为:白桦青扦山杨混交林>山杨纯林>白桦纯林>青扦纯林.枯落物浸泡时间与持水量之间合对数函数模型[Q=alnt+b(R^(2)>0.91)],浸泡时间与持水速率之间符合幂函数模型[V=Kt^(n)(R^(2)>0.99)].表层土壤层(0~5 cm)最大水量表现为:白桦青扦山杨混交林>白桦纯林>山杨纯林>青扦纯林.不同林地的表层土壤容重在0.28~0.47 g/cm^(3)之间,总孔隙度在57.26%~76.51%之间.【结论】从枯落物与表层土壤的持水指标、生物量以及渗透率等指标来看,白桦青扦山杨混交林水源涵养功能优于3种纯林.

【Objective】To study the water conservation function of Picea wilsonii,Betulapla typhylla,Populus davidiana and the mixed of three stands in Huzhu Beishan National Forest Park,Qinghai Province,in order to lay the data and theoretical foundation for soil and water conservation and conifer broad-leaved mixture in this region.【Method】Through the establishment of 28 m×28 m tree plots,collected litter and soil samples,use the indoor soaking and measuring method to determine the index.【Result】1)The maximum water holding capacity of different litter were mixed Betula platyphylla,Picea wilsonii and Populus tremula>Populus tremula>Betula platyphylla>Picea wilsonii.The relationship between the water holding capacity and the soaking time follows the logarithmic model,while the relationship between the proportional water holding capacity and the soaking time follows the power model.2)The water storage capacity of the soil layer(0~5 cm)is as follows:mixed Betula platyphylla,Picea wilsonii and Populus tremula>Betula platyphylla>Populus tremula>Picea wilsonii.3)The bulk density of the surface soil of different forest stands is between 0.28~0.47 g/cm^(3),and the total porosity concentration is between 57.26%~76.51%.There is little difference of the physical properties of water in different forest stands.【Conclusion】The water holding capability of mixed of Betula platyphylla,Picea wilsonii and Populus tremula are better than the other three forest stands.From litter and surface soil,the water holding capability of mixed Betula platyphylla,Picea wilsonii and Populus tremula forest are better than the other pure forest.