赖雁南 钟全林 李宝银 程栋梁 余华 徐朝斌 薛翔海 郑文婷

摘 要 氮沉降背景下毛竹向常綠阔叶林扩张问题是当前我国亚热带区域面临的主要生态问题与研究热点之一。以毛竹、竹阔混交林及常绿阔叶林为对象，通过1 a的氮添加试验，分析毛竹与常绿阔叶林木在不同植被类型中生长的差异，以探究氮沉降对不同植被类型中毛竹与常绿阔叶林木生长的影响。结果显示：（1）竹阔混交林中毛竹的平均胸径增长量、平均单株生物量增长量及生物量相对生长速率高于毛竹林中的毛竹，但竹阔混交林中阔叶林木的平均胸径增长量、平均单株生物量增长量及生物量相对生长速率则显著低于常绿阔叶林中的阔叶林木（P<0.05）;（2）低氮添加会减小毛竹在竹阔混交林与毛竹林中的个体差异，但会增大常绿阔叶林木在竹阔混交林与常绿阔叶林之间的生长差距，低氮添加有利于毛竹向常绿阔叶林扩张;（3）高氮添加会显著抑制毛竹的生长，一定程度上可减缓毛竹向常绿阔叶林扩张的速度。

关键词 氮添加;生物量;相对生长速率;毛竹;常绿阔叶林木

中图分类号：S714.8;S718.54     文献标识码：A   doi：10.13601/j.issn.1005-5215.2021.02.001

Abstract The expansion of Phyllostachys pubescens to evergreen broadleaved forests under the background of nitrogen deposition is one of the main ecological problems and research hotspots facing China's subtropical regions. Taking Phyllostachys edulis，Phyllostachys edulisevergreen broadleaved mixed forest and evergreen broadleaved forest as the object，the growth difference between Phyllostachys edulis & evergreen broadleaved forest in different vegetation types were analyzed through 1year nitrogen addition test，and explores the influence of Phyllostachys edulis expansion into evergreen broadleaved forest under the background of nitrogen deposition on the growth of Phyllostachys edulis and evergreen broadleaved forest. Results showed that： （1） In Phyllostachys edulisevergreen broadleaved mixed forest average growth in DBH，average individual biomass growth and biomass per plant relative growth rate is greater than Phyllostachys edulis in Phyllostachys edulis forest，Phyllostachys edulisevergreen broadleaved mixed forest，evergreen broadleaved forest significant differences mainly growth parameters，Phyllostachys edulis expansion leads to the average individual DBH growth rates of evergreen broadleaved forest biomass growth and biomass per plant and average relative growth rate dropped significantly;（2） Low nitrogen addition can reduce the growth difference of Phyllostachys edulis in Phyllostachys edulisevergreen broadleaved mixed forest and Phyllostachys edulis forest，but increase the growth difference of evergreen broadleaved forest in Phyllostachys edulisevergreen broadleaved mixed forest and evergreen broadleaved forest. Low nitrogen addition is beneficial to the expansion of Phyllostachys edulis into evergreen broadleaved forest;（3） The addition of high nitrogen can significantly inhibit the growth of Phyllostachys edulis and alleviate the expansion of Phyllostachys edulis to evergreen broadleaved forest.

Key words nitrogen addition;biomass;relative growth rate;Phyllostachys edulis;evergreen broad leaved trees

氮（N）是陆地生态系统净初级生产力最主要的限制元素之一[1，2]。工业革命以来，人类生产生活方式的改变使得全球大气活性氮化合物含量上升 [3]，导致大气氮沉降格局的改变。当前世界氮沉降分布中心正由欧美等老工业基地转移至各发展中国家，出现由温带逐渐扩散至热带亚热带的趋势[4]。……