北京密云油松人工林降水化学性质研究

Chemical properties of precipitation in Pinus tabulaefomis plantations.

为了揭示北京密云水库库区水源保护林涵养水源、改善水质的作用机理和规律,为北京密云水库库区水源保护林的经营与管理提供理论依据.在密云水库水源保护区上游油松人工林样地中,分别收集林冠、树干、枯落物层和土壤层雨水进行水化学性质分析.结果表明:大气降水中化学元素含量变幅较大,加权值排序为:Ca>N>K>Na>Mg>Fe>P>Zn>Cu>Mn,其加权平均值之和为10.817 mg/L;大气降水经过油松林林冠、树干、枯落物层及土壤层后,化学元素含量加权平均值之和分别为14.011、29.165、20.724和51.704 mg/L.由此可知,大气降水经过林层后,尽管各化学元素含量变化不一,但总含量却呈增加趋势,特别是经土壤层后增幅更大.

To reveal the mechanisms and laws that water resources protection forest preserves and improves water quality and to provide theoretical basis for managing and supervising protection forests,the authors studied the chemical properties of precipitation through collecting rainwater from canopy,trunk,litter and soil layer in Pinus tabulaeformis water resources protection forest in Miyun Reservoir,Beijing,from June 1 to September 15 of 2005.Results showed that chemical element contents in water varied greatly in the order of Ca>N>K>Na>Mg>Fe>P>Zn>Cu>Mn.The concentration of chemical elements of total precipitation was 10.817 mg/L.The concentration of total chemical elements of through-fall,stem-flow,litter water and soil-layer water were 14.011,29.165,20.724 and 51.704 mg/L respectively.The authors conclude that: the contents of chemical elements of through-fall,stem-flow,litter and soil layer water varied,but the total contents increased in comparison with that of the precipitation and it increased greatly especially through soil layer.It agrees with the study results of other scholars in China.