武夷山甜槠林生态系统的养分平衡研究

THE NUTRIENT BALANCE OF THE CASTANOPSIS EYREI FOREST ECOSYSTEM IN THE WUYI MOUNTAINS

本文通过比较大气降水的养分输入与由地表径流和地下渗流的养分输出，对武夷山甜槠林生态系统的养分平衡进行了研究。结果表明：在１９９３年４月至１９９４年４月期间，通过大气降水进入甜槠林的养分元素以Ｎ最高，为３４．２０７ｋｇ·ｈｍ－２，其余依次为Ｃａ（２２．９９ｋｇ·ｈｍ－２）、Ｓ（１２．７２２ｋｇ·ｈｍ－２）、Ｎａ（６．６７９ｋｇ·ｈｍ－２）、Ｋ（３．５５８ｋｇ·ｈｍ－２）和Ｍｇ（２．０５７ｋｇ·ｈｍ－２），以Ｐ的输入最低，仅１．７７９ｋｇ·ｈｍ－２；由地表径流和地下渗流的养分输出总量Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ、Ｓ、Ｎａ分别为５．６８、１．０１６、７．３４５、３．４３０、０．６２０、０．５３４、０．５７６ｋｇ·ｈｍ－２，以Ｋ的输出量最高，Ｓ的输出最少。其中，通过地下渗流的养分损失占输出总量的８５．９７％～９６．３８％，而地表径流的养分输出仅占总输出的３．６２％～１４．０３％；在该系统中，Ｎ、Ｃａ和Ｓ有大量的积累（分别为２８．５２７、１９．５６０和１２．１８８ｋｇ·ｈｍ－２），Ｍｇ和Ｎａ有少量积累（分别为１．４３７和６．１０３ｋｇ·ｈｍ－２），Ｐ基本上处于平衡状态（０．７６３ｋｇ·ｈｍ－２），而Ｋ则为净的输出损失（－３?

The nutrient balance was determined in a subtropical evergreen broadleaved forest ecosystem in the Wuyi Mountains from the difference between the precipitation input of nutrients per hectare and the nutrient output via runoff and drainage per hectare.The results showed that there were large apparent accumulations of nitrogen,calcium,and sulphur,and inputs of magnesium and sodium from the atmospheric precipitation were slightly higher than losses through leaching.Phosphorus appeared to be in close balance in the forest,but there was a net loss of potassium during the period of the study.The weathering of parent material may have played an important role in the potassium economy of the forest.For other nutrients,the forest could maintain itself on nutrient input from the atmosphere.