9种桉树幼林营养元素累积特性研究

为了研究在相同立地和养分供给条件下,不同桉树的生物量和营养元素(N、P、K)累积量及其分配特征,以1年生9种桉树(尾叶桉、窿缘桉、细叶桉、大叶桉、赤桉、巨桉、粗皮桉、托里桉、大花序桉)为材料,通过测定树根、树干、树皮、叶片、树枝5个器官的生物量以及氮、磷、钾含量,了解养分吸收和分配情况,揭示生物量构成特点。结果表明:9种桉树总生物量最大的是赤桉,为711.20 g·株-1,其次是托里桉、粗皮桉、巨桉、大叶桉、细叶桉、尾叶桉和大花序桉,窿缘桉的生物量最小,为69.20 g·株-1。不同器官生物量分配规律为树干或叶片最大,树根、树枝、树皮次之。不同器官营养元素含量为叶片最高,树干最低。9树种营养元素累积总量由高到低排序为赤桉(29)托里桉(29)巨桉(29)大叶桉(29)粗皮桉(29)细叶桉(29)尾叶桉(29)大花序桉(29)窿缘桉,各树种对3种元素累积量均为N最多,其次是K,P最少;9树种对N、P和K的吸收效率范围为分别为0.80%~7.69%,0.11%~1.32%和0.61%~10.38%;吸收效率最高的为赤桉,最低的为大花序桉,而其他桉树对各元素的吸收效率规律各不相同。

Accumulation of Mineral Elements in Plantations of Nine Different Eucalyptus Species

To investigate the distribution and accumulation characteristics of the biomass and nutrients under different Eucalyptus species, site and nutritional conditions were examined by measuring the biomass and nitrogen, phosphorus, potassium contents of five organ tissues of the trees (root, stem-wood, bark, leaf and branch) in nine eucalypt species: Eucalyptus cloeziana,E.pellita,Corymbia torelliana,E.robusta,E. camaldulensis,E.grandis,E.urophylla,E.exserta and E.tereticornis.At age one year, the efficiencies of nutrient absorption as well as nutrient distribution were estimated to reveal the characteristic compositions of the biomass of the different species.The results showed that E.camaldulensis has the largest total biomass (711.20 g·plant-1),followed by C.torelliana,E.pellita,E.grandis,E.robusta,E.tereticornis,E.urophylla,E. cloeziana,and then E.exserta,the latter having the smallest biomass(69.20 g·plant-1).In all species,most of the biomass was found in leaves and stem-wood, and then in roots, branches and bark. Leaves were also found to have the highest nutrient contents, but stem-wood had the lowest nutrient contents. The total nutrient accumulation amounts of the nine species ranked from that with the highest to that with the lowest were: E. camaldulensis,C.torelliana,E.grandis,E.robusta,E.pellita,E.tereticornis,E.urophylla,E.cloeziana and E.exserta.Different Eucalyptus species showed coincident trends in the accumulation of the three nutrients, of which the accumulation of N was the highest, followed by K and P. The absorption efficiency of these three nutrients in the nine different species ranged from 0.80% to 7.69% for N, 0.11% to 1.32% for P, and 0.61% to 10.38% for K.E.camaldulensis was found to have highest absorption efficiency whilst E.cloeziana had the lowest, but absorption efficiencies for various elements in the other species showed no consistent rankings.