青海大通不同树种水源涵养林对水质的影响

Effects of Water Conservation Forest of Different Tree Species on Water Qualities in Datong,Qinghai

选取青海大通水源区宝库林场青海云杉、华北落叶松、白桦、青杨、云杉-白桦混交林、云杉-落叶松混交林、沙棘林共7个样地,测定大气降水、穿透水、树干流中化学元素的含量以及河水TN、TP含量,分析水源涵养林不同树种对测定指标的影响。结果表明:青海大通水源区大气降水化学元素含量顺序为Ca>N>S>Na>K>Mg>P>Zn>Mn>Fe>Cu;各林种穿透水、树干流中各化学元素含量较大气降水总体上呈增长趋势,增长趋势相似,其中增幅最大的是Ca元素;穿透水Ca增长量最大的云落混交林,净增长26.59mg/L,树干流落叶松净增长为120.43mg/L;穿透水中青杨和云杉对Mn有吸附作用,沙棘、白桦、青杨、云杉、云杉白桦混交林对Zn表现出一定的吸附作用,树干流中云杉对Na、N、P呈现出吸附作用,树干流Na含量是穿透水的27%,N为84%,P为5%,沙棘和青杨对P元素也表现为吸附作用,吸收率分别为32%和33%;河水中的TN、TP有一个较好的消减作用,消减率分别为60.71%和69.94%;相关性分析表明,同一种元素不同树种间大部分呈现出显著差异性,同树种不同元素间有一定的相关性;通过穿透水、树干流水质的主成分分析,得到不同树种水质的贡献程度最大的是云落混交林和华北落叶松林。

Seven samples in Baoku,Datong,Qinghai were chosen to measure the concentrations of chemistry elements in precipitation,through-fall and stemflow and the concentrations of TN,TP in river,including Picea crassifolia,Larix principis-rupprech Mayri.,Betula platyphylla Suk.,Populus cathayana,Picea crassifoliaand Betula platyphylla mixed forest,Picea crassifolia and Larix principis-rupprechi mixed forest and Hippophae rhamnoides.Through analyzing the impacts on measured indicators of different trees in water conservation forest,we can draw some conclusions as follow：The order of chemical elements content in precipitation is Ca〉N〉S〉Na〉K〉Mg〉P〉Zn〉Mn〉Fe〉Cu.There is an increasing trend of chemistry elements in through-fall and stem-flow of different trees in contrast with the contents of precipitation.besides,this trend is similar.In all these indicators,Ca has a greatest increase.In Picea crassifoliaand Betula platyphylla mixed forest of throughfall has reached 26.59mg/L and 120.43mg/L in Larix principis-rupprechi of stem-flow;Populus cathayana and Picea crassifolia show a great abilities of absorbing Mn,Hippophae rhamnoides,Betula platyphylla,Populus cathayana,Picea crassifolia and Picea crassifolia and Betula platyphylla mixed forest has a certain absorption of Zn,and Picea crassifolia show a good absorption of Na,N,P in stem-flow;the content of Na in stem-flow is account for 27% of through-fall,and 85%for N,5%for P;Hippophae rhamnoides has an absorption rate of 32% and Populus cathayana has a absorption rate of 33% on P.TN,TP show a good reduction in river and the reduction rate reach 60.71%and 69.94%.For the same element we can get a significant difference（P0.05）in different tree species.There are some correlations between all the elements of the same tree species.Picea crassifoliaand Larix principis-rupprechi mixed forest and Larix principis-rupprechi contribute most to water quality considering principal component analysis to though-fall and stemflow.