桂西北12年生光皮桦人工林养分积累及其分布特征

Nutrients Accumulation and Distribution of 12-year-old Betula luminifera Plantation in Northwest Guangxi

采用标准样地法对广西天峨县12年生光皮桦人工林5种养分元素(N、P、K、Ca、Mg)的含量、积累量及其分配特征进行了研究。结果表明,光皮桦各组分养分含量由大到小依次为树叶、树枝、干皮、树根、干材;不同器官养分元素含量以N、K或Ca最高,其次是P,Mg最低。12年生光皮桦人工林养分积累量为1118.37 kg/hm2,其中乔木层、灌木层、草本层和凋落物层养分积累量分别为930.18、64.88、35.34和87.97 kg/hm2,分别占养分总积累量的83.17%、5.80%、3.16%和7.87%。光皮桦人工林5种养分元素年净积累量为77.53 kg/hm2,不同器官年净积累量排序为干材>树枝>干皮>树叶>树根。

The contents, accumulation, and distribution of five nutrient elements（N,P,K,Ca, and Mg） in 12-year-old Betula luminifera plantation in Tian＇e County, Guangxi were studied by standard sample plot method. The results showed that the nutrient contents in various organs were in the order of leaf〉branch〉stem bark〉root〉stem; the contents of N,K and Ca were the highest, P ranked the second, and Mg was the lowest in various organs. The total nutrient accumulation was 1118.37 kg/hm^2. The nutrient accumulations were 930.18,64.88, 35.34 and 87.97 kg/hm^2 for the tree layer, shrub layer herb layer and litter layer, accounting for 83.17 %, 5.80 %, 3.16 % and 7.87 %. respectively. The annual net accumulation of five nutrient elements was 77.53 kg/hm^2, the order of annual net accumulation of nutrient elements in different organs was stem〉 branch〉 stem bark〉 leaf〉 root.