滇中高原磨盘山常绿阔叶林营养元素分配格局

Distribution Pattern of Nutrient Elements of Evergreen Broad-leaved Forest in Mopanshan,Middle Yunnan Plateau

对滇中高原磨盘山常绿阔叶林群落的N、P、K、Ca和Mg这5种营养元素的质量分数、积累及分配格局进行研究,结果表明：乔木层植物叶片营养元素N、P、K、Ca、Mg质量分数分别为14.805~21.337、0.574~1.361、2.097~13.851、2.846~12.780、0.680~2.839 g·kg-1;不同植物种对营养元素具有选择吸收性,除树枝外,各器官营养元素质量分数均以N最高,其次是K和Ca,Mg和P最低;除Ca外,各营养元素质量分数在树叶中最高,树干中最低;Ca和Mg质量分数显著低于中国亚热带森林平均水平,是影响磨盘山森林生产力的重要因素;群落营养元素总积累量为5 125.185 kg·hm-2,乔木层、灌木层、草本层和凋落物层营养元素积累量所占比例依次为78.581%、4.461%、0.007%和16.951%,凋落物营养元素积累量明显高于林下植被层,林木归还给土壤的养分较为丰富,能够维持该生态系统的稳定和平衡;绝大部分树种属于P限制型植物,磨盘山常绿阔叶林植物生长总体上受P的制约。

We studied the nutrient （ N, P, K, Ca and Mg） distribution pattern and accumulation of evergreen broad-leaved forest in Mopanshan in Yuxi, middle Yunnan plateau, southwest China. The nutrient contents in leaves of the tree layer were 14.805-21.337 g · kg^-1for N, 0.574-1.361 g · kg^-1 for P, 2.097-13.851 g· kg^-1 for K, 2.846-12.780 g· kg^-1for Ca, and 0.680-2.839 g · kg^-1for Mg, respectively. Plants had the selective absorption of nutrient elements. N was the nutrient element with highest content of each organ except the branch, followed by K and Ca, and Mg and P had the lowest contents. Each nutrient element had the highest content in the leaf and the lowest in the stem except Ca. The correlation between the content of each nutrient element in leaves was poor. There was just a significant correlation between K and Mg. The contents of Ca and Mg were significantly lower than the mean level of subtropical forest in China, which were important factors that affected the forest productivity of Mopanshan. The whole community accumulation of nutrients was 5 125.185 kg · hm-2. The tree layer accounted for 78.581%, the shrub layer accounted for 4.461%, the herb layer accounted for 0.007% and the litter layer accounted for 16.951%. Litter nutrient accumulation was significantly higher than that of the undergrowth layer. It could maintain the stability and balance of the ecosystem. The plants were almost restricted by P. The growth of evergreen broad-leaved forest plants of Mopanshan were restricted by P on the whole. P is the limiting factor for this community productivity.