不同林分密度杉木林养分积累与垂直空间分配

在对1800、3000和4500株hm-23种密度杉木林生长调查及生物量测定的基础上,测定3种密度杉木林各组分养分含量和养分积累量,研究其地上部分养分积累量的垂直空间分配,为杉木林高效培育提供科学依据.结果 表明:1800、3000和4500株·hm-2杉木林养分积累总量分别为1311.57、2531.55和2307....

Characteristics of nutrient accumulation and vertical spatial distribution in Cunninghamia lanceolata plantation with different stand densities

The growth, biomass, nutrient content and accumulation as well as the vertical distribution of nutrient accumulation in Cunninghamia lanceolata plantation across densities of 1800, 3000, 4500 trees·hm^-2 were stu-died in order to provide scientific basis for efficient cultivation of C. lanceolata plantation. The total amounts of nutrients accumulated in C. lanceolata plantation with 1800, 3000, 4500 trees·hm^-2 were 1311.57, 2531.55 and 2307.33 kg·hm^-2, respectively. There were significant variations among different densities. Under the same density, the order of nutrient content and accumulation in C. lanceolata plantation was total N > total K > total Ca > total Mg > total P. Moreover, the amount of nutrients in trunk and bark decreased with the increases of tree height. The amount of nutrient accumulation in persistent withered branch and leaf were allocated from middle to the upper part of tree, while the opposite was observed for fresh branch and leaf. N accumulation increased with the increases of stand densities, while the other nutrients first increased then decreased. The order of the amount of nutrient accumulation in trunk, bark, root, persistent withered branch, persistent withered leaf and litter among different densities was 4500 > 3000 > 1800 trees·hm^-2, and was 3000 > 1800 > 4500 trees·hm^-2 in fresh branch and leaf, and 1800 > 3000 > 4500 trees·hm^-2 in understory. Under the densities of 1800 and 4500 trees·hm^-2, the nutrient distribution ratio in bark was the largest, accounting for 21.6% and 19.4%. In 3000 trees·hm^-2, the distribution ratio of fresh leaves reached its maximum, accounting for about 22.9%, and the next was fresh branches, which had a distribution ratio of about 17.8%. 3000 trees·hm^-2 was the most appropriate density for nutrient accumulation and distribution in C. lanceolata plantation.