黄土高原小麦田土壤呼吸季节和年际变化  

Seasonal and interannual variability in soil respiration in wheat field of the Loess Plateau,China

作　　者：周小平[1,2] 王效科[1] 张红星[1] 庞军柱[3] 任玉芬[1] 侯培强[1] 刘文兆[3] 

机构地区：[1]中国科学院生态环境研究中心,城市与区域生态重点实验室,北京100085 [2]青海省环境科学研究设计院,西宁810007 [3]西北农林科技大学林学院,杨陵712100

出　　处：《生态学报》2013年第23期7525-7536,共12页Acta Ecologica Sinica

基　　金：中国科学院战略性先导科技专项资助项目(XDA05050602;XDA05060102);国家自然科学基金资助项目(71003092)

摘　　要：采用自行开发的全自动多通道通量箱法对黄土高原小麦田土壤呼吸变化特征进行了连年原位监测,在此基础上,采用斜率同质性模型(homogeneity-of-slop model,HOS模型)对农田土壤呼吸季节和年际变化的成因进行了解析。结果表明,在日尺度上,土壤呼吸主要受土壤温度的影响,呈现出明显的单峰变化趋势,在12:00左右达最大值。季节尺度上,土壤呼吸冬季较低,春季上升,7月下旬达最大值,之后下降,土壤呼吸季节变化主要受土壤温度和湿度的影响。土壤呼吸年际间变化较大,其变化幅度为815.72—980.12 g C·m-2·a-1。土壤温度是引起土壤呼吸年际变化最重要的因素,逐步回归分析表明,土壤温度和土壤含水量均与土壤呼吸呈显著的正相关,可以用R soil=1.761+0.119T soil-1.30SWC,(R2=0.48,P<0.0001)来描述土壤呼吸与土壤温度和土壤水分的关系。降水量与土壤呼吸没有显著的相关关系。用HOS模型对土壤呼吸年际变化的成因进行分析的结果表明,功能变化(FC)、环境因子季节变化、环境因子年际变化以及随机误差分别可以解释年际变化的10.6%、58.4%、4.5%和26.5%,功能变化对土壤呼吸年际变化的影响要大于土壤温度年际变化的影响。因此,在土壤呼吸的预测中,不能仅仅依靠环境因子的变化来预测土壤呼吸的变化,还必须考虑到功能变化对土壤呼吸的影响。The interannual variability （IAV） in soil respiration （R_soil） is crucial for learning the carbon budget in the global climate change, the factors and the processes controlling the soil respiration. Variability in climate factors may directly control changes in the R_soil, but also may indirectly control the R_soil by ＂function change＂ by changing the biological and ecological processes. We measured the soil respiration and climate factors （ air temperature, soil temperature, soil water content and precipitation ） on the winter wheat farmland in the Loess Plateau, China, for four growing seasons. The homogeneity-of-slope model （HOS model） was used to distinguish direct effect of IAV in soil respiration and the function change. The results indicated that the soil respiration had a very significant diurnal, seasonal and interannual variability. The diurnal variability was controlled by the soil temperature, reached the peak at 13：00--16： 00. The stepwise regressanalysis indicated that the seasonal variability in soil respiration was controlled by the soil temperature （ T_soil, ranged from -3.8℃ to 30.7℃ ） and soil water content （ SWC, ranged from 1.5% to 50.3% ）, both of them showed positive relationships with soil respiration that could be described by the function ： R_soil = 1.761＋0.119T_soil- 1.30SWC, （ R2 = 0.48, P〈0.0001 ）. The precipitation had no significant relationship with R_soil. The mean annual R_soil ranged from 815.72 g C-m-2. a-1 to 980.12 g C m-2 a-1. The interannual variability of R_soil was controlled by the soil temperature. The results of HOS model analysis indicated that function change, interannual climatic variability, seasonal climatic variability and random error explained 10.6% ,4.5% ,55.4% ,and 26.5%, respectively, of the observed variation in soil respiration. Function change account for more than twice the variance in soil respiration of interannual climatic variability, it suggests that the soil respiration in the future con not be predicte

关 键 词：土壤呼吸 年际变化 功能变化 农田 斜率同质性模型 

分 类 号：S512.1[农业科学—作物学] S154