秃杉人工林营养元素含量、积累与分配特征的研究

Concentrations,Accumulation and Distribution Characteristics of Nutrient Elements in Taiwania Flousiana Plantation

对广西南丹山口林场秃杉人工林的N、P、K、Ca和Mg等5种营养元素含量、积累和分配及其随林分年龄的变化趋势进行了研究。结果表明,不同组分营养元素含量大小次序为树叶>干皮>树枝>树根>干材;林木各组分营养元素含量以N,Ca或K最高,其次是P,Mg最低。8、14和28年生林分营养元素积累总量分别为574.79、833.21和1 214.11kg.hm-2,其中乔木层营养元素积累量依次占92.87%、86.74%和85.88%,林下植被层依次占2.02%、2.99%和4.62%,地表现存凋落物层依次占5.11%、10.27%和9.50%;乔木层均以N或Ca积累量最多,Mg最少;秃杉人工林不同组分营养元素积累量的分配随林分年龄的增长发生变化,由8年生和14年生以树叶和树枝为主,逐渐转移到28年生以干材和树皮为主。3个林分年龄秃杉林每积累1 t干物质需要5种营养元素总量分别为8.97、6.40和4.21kg,其中对N或Ca的需求量最大,Mg最少。

Taiwania flousiana, a rare species endemic to China, is naturally distributed to the southwestern part of Hubei province, the southeastern part of Guizhou province and the west of Yunnan province. Due to the virtue of high adaptability, fast growth, high timber ratio and timber quality, T. flousiana has been successfully introduced to the southern part of China since the 1970s. In order to understand the nutrients characteristics in T. flousiana plantation, the concentrations, accumulation and distribution of five nutrient elements （N, P, K, Ca and Mg） as well as their changes with growth of stands in T. flousiana plantations of three different stand ages （8- year old, 14-year old and 28-year old） were studied in Nandan Shankou Forestry Farm of Guangxi, China. The results showed that concentrations of these five nutrient elements in different components of T. flousiana plantation were in the order of leaves 〉 bark 〉 branch 〉 root 〉 stem. And in different diameters of the root （ expect Stump）, nutrient concentrations reduced with the increase of root diameter. In plant, concentrations of N, Ca or K were the highest among the five elements, followed by P, while Mg was the lowest in various organs of T. flousiana plantation and in the litter. The total nutrient accumulations at three different stand ages plantations were 576.26 kg/ha, 833.20 kg/ha and 1214. 11 kg/ha, respectively. Of the total storage of nutrients, 85.88% -92.89% was distributed in arbor layer, 2.01% - 4.62% in forest floor layer and 5.10% -10.27% in standing litter layer. Among five elements, N or Ca accumulation in arbor layer was the highest and Mg accumulation in arbor layer was the lowest. The accumulations of nutrients in T. flousiana varied with different stands growth stages. Most nutrient elements accumulated in leaves and branches at 8-year-old and 14-year-old trees, while they transmitted gradually to the stem and bark at 28-year-old trees. The net production of organic matter per ton needed five elements in plantations from 4.21 kg to 8.97 kg and decreased with the biomass accumulation in the process of the stands growth. And the N or Ca element amount was the biggest, then the K and Ca, and the Mg was the smallest among the five nutrient elements.