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在福建平和天马林场 ,对尾叶桉生长过程中营养元素的动态变化进行了为期 5a的研究 .结果表明 ,尾叶桉平均每年胸径增长 2 .46cm ,树高增长 2 .5 0m ,枝、叶、干 (干材和干皮 )和根中 5种主要营养元素的总量 (N +P +K +Ca +Mg)分别为 17.11gkg- 1 、33.38gkg- 1 、9.6 6gkg- 1 和 12 .75gkg- 1 ,平均每年吸收 5种主要营养元素量 338.31kghm- 2 a- 1 ,平均每年纯吸收 5种主要营养元素量 188.2 1kghm- 2 a- 1 ,平均每年归还 5种主要营养元素量 15 0 .10kghm- 2 a- 1 ,平均循环率为 44.37% .表 4参 6
The results showed that the average diameter of Eucalyptus urophylla increased by 2.46cm and the tree height increased by 2.50m, branches and leaves (N + P + K + Ca + Mg) were 17.11gkg-1, 33.38gkg-1, 9.66gkg-1 and 12 respectively in stem, stem and root, and root. 75gkg-1, the average annual absorption of five kinds of main nutrient elements 338.31kghm-2 a- 1, the average annual pure absorption of five kinds of main nutrient elements 188.2 1kghm- 2 a- 1, the average annual return of 5 kinds of main nutrient elements 15 0 .10kghm-2 a-1, the average cycle rate of 44.37%