田林老山中山杉木人工林凋落物及其分解作用的研究

STUDIES ON THE LITTERFALL AND ITS DECOMPOSITION OF CHINESE FIR PLANTATION IN MID-MOUNTAIN REGION OF LAOSHAN,TIANLIN COUNTY,GUANGXI

本文是广西森林生态系统研究项目的一部分,旨在阐明高海拔山区杉木人工纯林凋落物的产量动态、营养元素含量及其分解速率,并分析比较两种置样处理对凋落物分解作用的影响,为营林提供参考依据。一、实验区条件与样地概况老山杉木林区位于北纬24°16′、东径106°19′,海拔1300-1600m,属于桂西北山原地区。年平均气温14℃,最冷月(1月)均温5.6℃,最热月(7月)均温21.3℃。年降雨量1611.5mm,夏秋两季雨量分别占全年的50.4％和23.4％。年相对湿度88％、水热系数3.82,属冬干冷夏湿凉气候型。

This paper studied the production and nutrient element contents of litterfall in Chinese fir plantation as well as its decomposition placed on the soil above ground and in soil underground in midmountain region of Laoshan,Tianlin county, Guangxi. The results indicate: 1. The mean annual litter in 17-19-year-old Chinese fir plantation is5.176 t·ha^(-1) in Laoshan. 2. Total amount of nine nutrient elements of the litterfall returing to thesoil is 118.86 kg·ha^(-1)·a^(-1), in which N 39. 43, P 2. 02, K 7. 65, Ca 54. 80,Mg 11.68, Mn 3.07, Cu 0.05, Zn 0.12 and B 0.04 kg·ha^(-1)·a·^(-1) 3. The decomposition of litterfall on the soil above ground is comparati-vely slow and the decay rates of the leaf, branch and fruit are 0.3308, 0.2062and 0.2358 g·g·^(-1)a^(-1) respectively. 4. The rate of weight loss, the rate of translocation of nutrient elementsand the quantity of the various groups of microorganisms of the litterfall insoil undergound (20cm) are higher than that on the soil above ground.