广东黑石顶森林群落凋落叶的研究

A RESEARCH OF LITTER LEAF IN THE FOREST COMMUNITY OF HEISHIDING IN GUANGDONG

本文工作是以黑石顶自然保护区森林群落为对象,在不同生长季节对凋落叶量与地被物现存量及其降解与营养回归进行了为期一年的研究.结果表明: 1、平均年凋落叶量为 3.468±0.196 t·ha^(-1),占叶现存生物量的20-22％。地被枯叶量为 3.078t·ha^(-1).每季度的总凋落叶量和每个树种的凋落叶量在总凋落叶量中的比例随季节而波动. 2、凋落叶中灰分、有机 C、全 N、全 P的年平均含量以绝对于物质计分别为4.11％、47.78％、0.8216％、0.0476％,含量最高值出现在雨季,最低值在干季.全K年平均含量为0.2653％,但含量最高在干季、最低在雨季,这是因为K很容易被淋溶.经过一年的降解,有机C、全N、全P、全K的含量分别降至38.85％、0.5118％、0.0367％和0.2223％。 3、经推算,全 P、全K、全N在凋落叶中的含量分别是在生活叶中含量的15.87-31.73％,17.69-26.53％,27.39-54.77％。这说明树叶中大部分的营养物质在凋落前已经通过某种途径发生了移动. 4、群落凋落叶半量降解时间平均约为3个月,失重率在雨季后期(6月～9月)最高(50.75％),干季(12月～3月)最低(6.28％).在一年时间里,凋落叶干物质的64.32％回归到土壤中,即2.2269t·ha^(-1).地被落叶在一年内的失重率为54.68％.

Litterfall, standing litter, and decomposition of litter leaf of Heishiding subtropical forest were studied for one year. Field samples were taken every three months. The seasonal dynamics of the nutrient return of litter leaf was analysed, and a frame of nutrient flux from litter leaf to the soil was founded quantitatively in south subtropical evergreen broad-leaved forest in Heishiding. The main results were as follows: 1. The standing litter leaf was about 3.078t. ha-1 the average production of litter leaf was 3.468± 0.196tha-1a-1, amounting to 20-22% of the standing biomass of living leaf. 2. The amount of total litter leaf of each species in each season was influenced by the climate. The contribution of each species for litter production was varied. 3. The half-decomposition time is about three months in this community. The highest rate of decomposition (50.75%)was in the later period of rainy season(June-September), and the lowest (6.28%) in winter (December-March). 4. The average contents of ash, organic C, total N and total P in the litter leaf were 4.11%, 47.78%,0.8216% and 0.0476%, respectively. Among four seasons, their highest contents appeared in the beginning of rainy season and the lowest contents were in winter. The average content of total K in the litter leaf was 0.2653%. Contrary to the results mentioned above, the highest content of K was in winter and the lowest in the beginning of rainy season, because K was readily to be washed away. After one year's decomposition, the content of organic C, total N, total P and total K were 38.85%, 0.5118%, 0.0367% and 0.2223%, respectively. 5. The calculated percentages of the average content of total P, total K and total N in the litter leaf were 15.87-31.73%, 17.69-26.53% and 27.29-54.77%, respectively, of those in the living leaf this data revealed that most nutrient was transferred from the leaves before littering. 6. Within one year, the nutrient of litter leaf returning to the soil was about 64.32% of the litter leaf dried weight, equaling to 2.2269t·ha-1. The lost weight of the standing litter leaf constituted 54.68% within a year.