不同森林类型地表径流水质特征分析与评价

Analysis and Assessment on the Surface Runoff Water Quality Characteristics in Difierent Forest Types

本文对安徽黄山森林生态系统国家定位观测研究站区域内的大气降水、不同森林类型地表径流的p H值等水质指标进行定位测定与分析。结果表明,该区域内大气降水在经过地表径流后,p H值由弱酸性变为弱碱性,DO、COD_(Cr)和NH_(3)-N被林地吸收浓度有所下降,N、P、Cl^(-)、SO_(4)^(2-)、Ca^(2+)、Mg^(2+)从土壤和岩石中释放,浓度有所上升;NO_(3)^(-)既被土壤溶淋降低,又释放呈升高状态。在不同森林类型的地表径流中,以苦槠、牛鼻栓、杜鹃和连蕊茶为主的林地类型,对NH_(3)-N和Tur表现了很好的吸附性,吸附效果分别达到45.8%和82.76%;以杜仲和茶树为主的林地类型,其TP的浓度低于大气降水的浓度;毛竹人工纯林消耗了大量DO,且土壤向水中释放了较高的P,使得水质变差;枫香、野鸦椿和胡枝子的林地类型及杜仲、杉木和枫香的林地类型,主要是流失了较高的Ca^(2+)、Mg^(2+)等阳离子。所有森林类型地表径流含量各不相同,阳离子含量均表现为Ca^(2+)>Mg^(2+);阴离子含量均表现为SO_(4)^(2-)>Cl^(-)>NO_(3)^(-)。通过综合水质指数计算分析方法对不同森林类型的地表径流进行计算,天然林对大气降水净化和水土保持能力较人工林表现更好。此研究旨在为深入研究不同类型森林水文的水质特征提供依据。

In this paper,fixed-point measurement and analysis were made on the atmospheric precipitation and pH value of surface runoff in different forest types within the region of Anhui Huangshan Forest Ecosystem National Permanent Observation Station.The results showed that in this area,the pH value of surface runoff became alkalescent from the faindy acid atmospheric precipitation,the concentration of DO,COD_(Cr) and NH_(3)-N decreased with absorption from forestland,N,P,Cl^(-),SO_(4)^(2-),Ca^(2+),Mg^(2+)were released from soil and rock with increased concentration and N03-increased as it is leached down by but released from soil.Among the surface runoffs of different forest types,forest types with dominant Castanopsis sclerophylla,Fortunearia sinensis,Rhododendron simsii,and Camellia cuspidala showed good adsoiption of NH_(3)-N and Tur with adsorption efiiects reaching 45.8%and 82.76%respectively.The concentration of TP in forest types with dominant Eucommia ulmoides and Camellia sinensis was lower than that of atmospheric precipitation.A lot of DO was consumed by pure Phyllostachys edulis plantation and the water quaEty got worse with a high content of P released from the soil.Ratively high portion of such cations as Ca^(2+),Mg^(2+)were washed away in the forest type of Liquidambar formosana,Euscaphis japonica and Lespedeza bicolor and that of Eucommia ulmoides,Cunninghamia lanceolata and Liquidambar formosana.The contents of surface runoffs were difierent among all the forest types,and the cation content was Ca^(2+)>Mg^(2+)and the anion content was all SO_(4)^(2-)>Cl^(-)>NO_(3)^(-).Comprehensive water quality index calculation and analysis of surface runoffs in different forest types indicated that natural forest has better capacity in purifying atmospheric precipitation and conserving soil and water than that of planted forest,which could provide basis for in-depth study of water quality characteristics in diflerent forest types.