杨树人工林生态系统凋落物生物量及其分解特征

发布时间：2018-06-04 03:35

本文选题：杨树人工林 + 生物量　；参考：《生态环境学报》2017年09期

【摘要】：凋落物是森林土壤有机质的主要来源,是森林生态系统物质循环和能量流动的重要载体。而凋落物分解是森林生态系统养分生物地球化学循环的重要过程,是土壤有效养分供应能力的决定因素之一,与森林生产力及可持续生长密切相关。通过研究杨树人工林凋落物生物量及其分解过程,掌握其养分数量及其释放规律,为人工林可持续经营提供重要依据。采用凋落物收集网法和凋落物分解袋法,对长江中下游地区南京市浦口区13年生的杨树(Populus deltoides Bartr.cv."Lux"I-69/55)人工林生态系统凋落物生物量以及不同类型凋落物的分解特征进行了系统研究,结果表明:杨树人工林凋落物生物量约为5t·hm~(-2)·a~(-1),叶片是凋落物的主要成分,占凋落物总量的70%左右;通过Olson指数模型拟合得出的各凋落物的半分解时间及95%分解时间均表现为杨树枯枝杨树枯叶混合凋落物枯死的林下植被杨树根系。2年连续分解试验表明,凋落物中的N整体上呈先富集后释放的模式,P整体上呈持续富集的模式,K呈早期释放模式,而Ca和Mg的释放模式比较复杂。分解2年后,杨树地上部分凋落物(枯叶和枯枝)养分总释放量(N、P、K、Ca和Mg的总和)为86.1 kg·hm~(-2),养分回归率约为60%;林下植被凋落物养分总释放量为92.3 kg·hm~(-2),养分回归率达75%以上,表明林下植被凋落物是杨树人工林生态系统养分归还的重要组成部分。
[Abstract]:Litter is the main source of organic matter in forest soil and an important carrier of material circulation and energy flow in forest ecosystem. Litter decomposition is an important process of nutrient biogeochemical cycle in forest ecosystem and one of the decisive factors of soil available nutrient supply ability. It is closely related to forest productivity and sustainable growth. The litter biomass and its decomposition process of poplar plantation were studied, and the nutrient quantity and its release law were grasped, which provided an important basis for sustainable management of plantation. The litter biomass and decomposition characteristics of different types of litter in the artificial forest ecosystem of Populus deltoides Bartr.cv. "Lux" I-69 / 55 in Pukou district of Nanjing city in the middle and lower reaches of Yangtze River were studied systematically by means of litter collection net method and litter decomposition bag method. The results showed that the litter biomass of poplar plantation was about 5 t / hm ~ (-2) / a ~ (-1), and leaf was the main component of litter, accounting for about 70% of the total litter. The semi-decomposition time and 95% decomposition time of each litter were obtained by Olson index model fitting. The results showed that the root system of poplar with mixed litter of poplar branches and poplar leaves was dead. The N in litter was first enriched and then released as a whole, and P was continuously enriched as a whole, and K was released at an early stage, but Ca and mg were more complicated. After decomposing for 2 years, the total nutrient release of the aboveground litter (leaf and branch) of poplar was 86.1 kg / hm ~ (-2), and the nutrient regression rate was about 60 ~ (-2), and the total nutrient release of litter was 92.3 kg / hm ~ (-2), and the recovery rate of nutrient was more than 75%. The results showed that litter was an important component of nutrient return in poplar plantation ecosystem.
【作者单位】：南京大学生命科学学院;南京林业大学林学院;环境保护部南京环境科学研究所//国家环境保护生物安全重点实验室;
【基金】：国家重点研发计划课题(2016YFD0600402) 江苏省林业三新工程项目(LYSX[2016]48) 国际科技合作项目(2011DFA30490) 环保部事业费项目“生物多样性保护专项”
【分类号】：S714

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