模拟氮沉降下去除凋落物对太岳山油松林土壤呼吸的影响

生态学杂志

模拟氮沉降下去除凋落物对太岳山油松林土壤呼吸的影响

李化山¹,汪金松²,赵秀海^1**,康峰峰¹,张春雨¹,刘星¹,王娜¹,赵博^1

（¹北京林业大学森林资源与生态系统过程北京市重点实验室，北京 100083； ^2中国林业科学研究院森林生态环境与保护研究所，北京 100091）

出版日期:2014-04-10 发布日期:2014-04-10

Effects of litter removal on soil respiration under simulated nitrogen deposition in a Pinus tabuliformis forest in Taiyue Mountain, China.

LI Hua-shan¹, WANG Jin-song², ZHAO Xiu-hai^1**, KANG Feng-feng¹, ZHANG Chun-yu¹, LIU Xing¹, WANG Na¹, ZHAO Bo¹

(¹Key Laboratory for Forest Resources & Ecosystem Processes of Beijing, Beijing Forestry University, Beijing 100083, China; ^2Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China)

Online:2014-04-10 Published:2014-04-10

摘要/Abstract

摘要： 凋落物是土壤呼吸的重要碳源，氮沉降将改变其输入数量和质量，进而影响土壤呼吸。为揭示氮沉降和去除凋落物对土壤呼吸的影响，以太岳山油松林为研究对象，对林地分别作2种凋落物处理：去除凋落物（LR）、对照（CK1），设计4个施氮水平：不施氮（CK2，0 kg N·hm^-2·a^-1），低氮（LN，50 kg N·hm^-2·a^-1），中氮（MN，100 kg N·hm^-2·a^-1）和高氮（HN，150 kg N·hm^-2·a^-1），于2010—2012年生长季测定土壤呼吸速率的动态变化，并分析土壤呼吸速率与土壤温度、土壤湿度、土壤微生物生物量C、N的关系。结果表明：随着观测年限的推移，模拟氮沉降对对照处理的土壤呼吸速率、去凋处理的土壤呼吸速率、凋落物层呼吸速率的促进作用逐渐减弱。去除凋落物使土壤呼吸速率降低了29.0%，施氮减小了去除凋落物后土壤呼吸速率的变化幅度。土壤呼吸速率与土壤温度均呈显著指数相关（P<0.05），土壤温度解释了土壤呼吸速率变异的37.3%～62.2%，去除凋落物降低了模型决定系数R²；以土壤温度和土壤水分构建的复合关系方程拟合效果均好于单因子模型，土壤温度和水分共同解释了土壤呼吸季节变化的67.6%～85.6%，并且施氮降低了去凋处理的复合模型决定系数R²，而对对照处理没有显著影响。施氮提高了土壤微生物生物量C、N，并且土壤微生物生物量C、N与土壤呼吸速率呈显著正相关（P<0.05）。说明氮沉降、凋落物是影响油松林土壤CO₂通量的两个重要因子。

关键词: 退耕区域, 碳汇产业, 碳汇潜力, 经济增长点, 理论基础

Abstract: Litter respiration is a major component of soil respiration which would be affected by increasing nitrogen deposition via altering the quantity and quality of litter. In order to determine the influence of nitrogen deposition and litter removal on soil respiration, a threeyear field experiment under simulated nitrogen deposition with and without litter removal was conducted in a natural Pinus tabuliformis forest in Taiyue Mountain, Shanxi Province, China. Nitrogen levels were implemented as: CK (0 kg N·hm^-2·a^-1), LN (50 kg N·hm^-2·a^-1), MN (100 kg N·hm^-2·a^-1) and HN (150 kg N·hm^-2·a^-1). The relationships between soil respiration and soil temperature, moisture, microbial biomass after each nitrogen application were analyzed. Results showed that simulated nitrogen deposition promoted soil respiration in the control and litter removal subplots, and litter respiration at the early stage, but the promotion was weakened over time. The litter removal treatments decreased the average rates of soil respiration by 29.0%, and nitrogen deposition decreased the fluctuation of soil respiration after litter removal. A significant exponential correlation was found between soil respiration and soil temperature at 5 cm depth (P<0.05), which explained 37.3%-62.2% of the seasonal variation of soil respiration, and the litter removal treatments decreased the R² of all nitrogen levels. Four twovariable linear/nonlinear models with soil temperature and soil moisture appeared to have a good precision when used to predict the soil respiration, with R² ranging from 0.676 to 0.856, and nitrogen deposition decreased the R² of the litter removal treatments, but it did not significantly affect the R² of the control treatments. Simulated nitrogen deposition increased soil microbial biomass C and N, and the soil respiration exhibited a linear relationship with microbial biomass C and N. It was suggested that nitrogen deposition and litter were two important factors affecting soil CO₂ efflux in P. tabuliformis forests.

Key words: carbon sink industry, carbon sink potential, theoretical basis., de-farming region, economic growth point

李化山1,汪金松2,赵秀海1**,康峰峰1,张春雨1,刘星1,王娜1,赵博1. 模拟氮沉降下去除凋落物对太岳山油松林土壤呼吸的影响[J]. 生态学杂志.

LI Hua-shan1, WANG Jin-song2, ZHAO Xiu-hai1**, KANG Feng-feng1, ZHANG Chun-yu1, LIU Xing1, WANG Na1, ZHAO Bo1. Effects of litter removal on soil respiration under simulated nitrogen deposition in a Pinus tabuliformis forest in Taiyue Mountain, China.[J]. cje.