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根据 5 a定位观测的数据 ,对湖南会同 2 4~ 2 8a生的杉木人工林生态系统各水文学过程中的养分特性进行了研究。结果表明 :林冠降水是杉木人工林生态系统养分输入的重要来源 ,其中 Ca的养分含量最高 ,P的含量最低。林内穿透水各养分元素的含量明显高于林冠降水中养分的含量。除 Ca外 ,树干茎流中其它养分元素的含量为林冠降水的 6倍以上。可见 ,林内穿透水和树干茎流是杉木林生态系统内养分循环的重要组成部分 ,有利于提高系统的养分利用率。地表径流中除硝态氮外 ,各元素的含量与穿透水的含量接近 ,其中 P、Na和 K三种元素的含量较低 ,但未超过林冠降水中养分元素含量。地下径流中 N和 K的含量较低 ,而 Ca的含量与林冠降水相比没有差异。因而地表径流和地下径流不可避免的造成生态系统的养分损失 ,但 2 4~ 2 8a生杉木林生态系统的调控能力较强 ,地表径流和地下径流量较小 ,生态系统的养分损失也相对较小 ,养分为净积累。不同季节之间水文学过程中养分元素含量存在一定程度的差异。降水形态、雷电和地形等要素影响养分元素含量。硝态氮在冰雹中未检出 ,而在雨水中的含量是雪水的 2倍。铵态氮、K和 Mg等元素在雨水中的含量最高。P和 Ca以雪水的含量最高 ,与雨水和冰雹相比不存在数量级差异。雷电明显增?
According to the data of 5 years observation and observation, the nutrient characteristics of each hydrological course of the Chinese fir plantation ecosystem from 24 to 28 years old in Huitun were studied. The results showed that canopy precipitation was the important source of nutrient input of Chinese fir plantation ecosystem, of which Ca had the highest nutrient content and the lowest P content. The penetrating water content of nutrient elements in forest was obviously higher than that in canopy precipitation. Except for Ca, the content of other nutrient elements in the stem-stem flow is more than 6 times that of the canopy precipitation. Can be seen that penetration of water and trunk stem flow is an important component of the Chinese fir plantation ecosystem cycle of nutrients is conducive to improving the system of nutrient utilization. Surface runoff in addition to nitrate nitrogen, the content of each element is similar to the penetration of water, in which P, Na and K three elements of the content is low, but does not exceed the canopy precipitation of nutrient elements. The content of N and K in underground runoff is lower, while the content of Ca is not different from the canopy precipitation. Therefore, surface runoff and subsurface runoff inevitably lead to the loss of nutrients in the ecosystem. However, the control ability of the ecosystem of Chinese fir plantation from 24 to 48 years is stronger, and the surface runoff and subsurface runoff are smaller, and the nutrient loss in ecosystem is also relatively Small, nutrient accumulation for the net. There is a certain degree of difference in nutrient content between different seasons in hydrology. Precipitation patterns, lightning and topography and other factors affect the nutrient element content. Nitrate is not detected in hail, but is twice as abundant in rainwater as snow water. Ammonium nitrogen, K and Mg and other elements in the highest levels of rainwater. P and Ca have the highest levels of snow water, with no order of magnitude difference compared to rain and hail. Lightning increased significantly?