冀北山地华北落叶松林生态系统水化学特征

Precipitation Hydro-chemical Characteristic of North Deciduous Pine of North Mountain of Hebei Province

降水是森林生态系统的一个主要的养分输入源,观测并分析降水化学对于准确地估算森林生态系统养分循环的养分元素浓度显得极为重要。对冀北山地华北落叶松林穿透雨、树干茎流和枯透水中的Ca、Fe、K、Mg、Mn、Zn共6种养分元素进行了测定。结果表明:(1)大气降水经过林冠层后其水化学特征明显发生了变化,化学元素含量均有不同程度增加,含量排序为Ca>K>Mg>Fe>Mn>Zn,其中Mn元素的增长倍数最多,但6月份Mn和Zn元素浓度都出现负增长。树干茎流各项指标均增长很多,化学元素含量排序为Ca>K>Mg>Mn>Fe>Zn。枯落物水中K和Ca元素浓度增加最大。(2)大气降雨中Zn的变异系数最大,达2.853;K和Ca元素的变异系数最小,为0.158,0.163。落叶松林穿透雨、树干茎流和枯透水中最大变异系数分别为Fe元素3.115,Mg元素为1.288,Fe元素为2.139。(3)经过淋洗后水样中各元素的浓度均有所增加,穿透水、树干茎流和枯透水中K、Ca增加较多,Fe、Zn的淋溶量较少。

Because of precipitation serves as one of major approaches of nutrient input into the forest ecosystem,the accurate measurement of its volume and ion concentration is of prime importance in an evaluation of nutrient biogeochemical cycle.The contents of six nutrient elements（Ca,Fe,K,Mg,Mn,Zn） in through-fall,stem-flow and litter water were measured in the larch forest of North Mountain of Hebei Province.The results showed that：（1）Precipitation canopy layers after its hydrochemistry characteristic obviously changed,chemical element content to have the varying degree increase,chemical element content Ca〉K〉Mg〉Fe〉Mn〉Zn,among the growth of most multiples was Mn,but Mn and Zn concentrations had shown negative growth in June.Trunk run off each index all increased a lot,chemical element content CaKMgMnFeZn.Withered falling objects water K and Ca element concentration increased the maximum.（2）The largest variation coefficient was Zn,in the rainfall of atmospheric,was 2.853;the smallest was K and Ca,was 0.158,0.163.Deciduous pine tree trunks through rain,withered stalk flow and variation coefficient were largest in permeable Fe elements for 3.115,Mg elements for 1.288,Fe element for 2.139.（3）Through leaching after samples of each element in the concentration increased,penetrate water,trunk run off and the withered permeable of K and Ca increased considerably,Fe,Zn leached of less.