赣南丘陵区典型林分水源涵养功能评价

目的]明确不同林分类型整体水源涵养能力的差异性,为赣南丘陵区水源涵养功能和生态系统服务的恢复提供理论依据。方法]以赣南丘陵区江西省赣州市崇义县境内两种主要天然林(楠木和毛竹),以及两种典型人工经济果林地(脐橙和茶)为研究对象,利用水浸法和双环法对林分的枯落物层与土壤层的持水性进行测定,同时利用熵权法对枯落物层和土壤层的相关指标进行综合评价。结果]①4种林分枯落物层蓄积量、最大持水量和有效拦蓄量范围分别为9.19~16.70,13.43~31.02,6.99~14.08 t/hm²;土壤非毛管孔隙度、有效持水量和最大持水量均值范围分别为5.80~10.05%,57.98~100.50,447.76~580.17 t/hm²,均为楠木林最大,茶林最小。②4种林地土壤初渗速率与稳渗速率变化趋势相一致,排列顺序为:毛竹林>楠木林>茶林>脐橙林。③在4种林分水源涵养能力综合评分中,两种天然林要高于两种经济果林。④土壤稳渗速率是影响林分整体水源涵养能力最显著的指标,其次为枯落物最大持水量和有效拦蓄量,而土壤容重的影响最低。结论]赣南丘陵区两种天然林水源涵养能力高于两种经济果林,而该区域人工经济果林水源涵养能力的大幅度降低将进一步导致土地退化,加速水土流失,是区域可持续发展的重要生态风险隐患之一。

Evaluation of Water Conservation Capacity of Litter and Soil Layer in Typical Forest Stands in Hilly Region of Southern Jiangxi Province

Objective]The variation in water conservation capacity in different stands was studied to provide a theoretical basis for the restoration of the water conservation function and ecosystem services in Southern Jiangxi Province.Methods]All experiments were conducted in Chongyi County,Ganzhou City,Jiangxi Province.Two main natural forests,Phoebe zhennan and Phyllostachys heterocycla,and two typical artificial economic fruit forests,Citrus sinensis and Camellia sinensis,were selected.The water holding capacity of the litter layer and soil layer was measured by the water immersion and double ring methods.Related indices of the litter layer and soil layer were evaluated by the entropy weight method.Results]①The litter volume,maximum water holding capacity,and effective interception capacity of the four kinds of stand were 9.19-16.70,13.43-31.02,and 6.99-14.08 t/ha,respectively.The average ranges of soil noncapillary porosity,effective water holding capacity,and maximum water holding capacity were 5.49%-10.05%,57.98-100.50 t/ha,and 447.76-580.17 t/ha,respectively.All traits in the P.zhennan forest were found to be greater than in the other stands,and the lowest were in the C.sinensis forest.②Four stands had similar changed tendencies of soil initial infiltration rate and stable infiltration rate.The order was P.heterocycla forest>P.zhennan forest>C.sinensis forest>C.sinensis forest.③The comprehensive scores of the water conservation capacity of the natural forests(P.zhennan forest and P.heterocycla forest)were higher than those of the economic forests.④The water conservation capacity of the stand was mostly affected by soil steady infiltration rate,followed by maximum water holding capacity and effective retention capacity of the litter,while the soil bulk density was the lowest.Conclusion]The water conservation capacity of natural forests is higher than that of economic fruit forests in the hilly area of South Jiangxi Province.The land degradation and accelerated soil erosion are driven by the reduction of the water conservation capacity of artificial economic forests in this area,leading to an important ecological risk to the sustainable development of this region.