林地土壤水源涵养多因素复合模拟研究——以苕溪流域为例

为了研究不同植被覆盖度、不同林相及不同林种林下土壤水源涵养的特性,以浙江省苕溪流域上游区为例,采用野外不同林种土壤持水能力定时定点实测取样、室内不同植被覆盖度(0,15%,30%,45%,60%,75%,90%)、不同林相(上层覆盖、下层覆盖、上下层覆盖)的物理模型人工模拟降雨试验方法,通过不同深度土壤水分含量测试、产汇流和入渗系数计算,探索了林地不同经营管理方式下土壤涵养水源的特性,结果表明:(1)地表入渗系数随植被覆盖度的增加而增大,随坡长增加入渗系数的增长比率增加,降雨过程中植被覆盖度对入渗系数的影响比坡长的影响大。(2)不同林相的模拟试验结果表明,地表入渗系数排序为上下层覆盖上层覆盖下层覆盖裸地。随着产流历时增加,林下土层的蓄水量呈线型增加,与裸坡比较,累积蓄水量增加百分数为:上层覆盖为23%,下层覆盖为29%,上下层覆盖为37%。(3)通过监测不同林地不同深度土壤含水率的变化,并与裸地进行对比得出不同林地涵养水源能力的强弱。其蓄水能力排序分别为板栗林茶园竹林。研究结果为林地管理、林相培育和林下土壤持水能力的提高具有科学方法论上的支撑和生产实践方面的借鉴。

Multi-factor composite simulation of soil water conservation in forest land: A case study of the Tiaoxi River Basin

The present study investigated the effects of vegetation coverage, forest form, and forest species on the soil water conservation capacity of forest land. The research was conducted in the upper reaches of the Tiaoxi River Basin (Zhejiang Province, China) and involved indoor artificial rainfall simulations. Physical models were obtained for different levels of vegetation coverage (0, 15%, 30%, 45%, 60%, 75%, and 90%) and different forest forms (upper cover, lower cover, upper and lower cover). In addition, the study also measured the water-holding capacity of soils at different depths in the field. Results indicated that:(1) The infiltration coefficient increased with the increasing vegetation coverage, increased more rapidly as slope length increased, and was affected more by vegetation coverage than slope length during rainfall. (2) The forest form simulation experiment indicated that the surface infiltration coefficient decreased as follows: upper and lower layer coverage > upper layer coverage > lower layer coverage > bare land. The amount of water stored in the forest soil increased linearly with the runoff duration, and the cumulative water storage of the three forest forms was 37%, 29%, and 23% greater than that of bare land, respectively. (3) This study monitored changes in soil moisture content at different depths and in different forests. By comparing intact forest (chestnut forest, tea garden and bamboo forest) with the bare land, the strength of the water source capacity of forest land was obtained. Water storage capacity decreased as follows: chestnut forest > tea garden > bamboo forest. These findings provide scientific methodological support and production practice that can be used for managing forest land, cultivating various forest forms, and improving soil water-holding capacity.