三江源区不同退化程度高寒草原土壤呼吸特征  

Characteristics of soil respiration in different degraded alpine grassland in the source region of Three-River

作　　者：温军[1,2] 周华坤[2] 姚步青[2] 李以康[2] 赵新全[2] 陈哲[2,3] 连利叶 郭凯先 

机构地区：[1]青海省水利水电科学研究所,西宁810001 [2]中国科学院西北高原生物研究所,西宁810008 [3]中国科学院大学,北京100049

出　　处：《植物生态学报》2014年第2期209-218,共10页Chinese Journal of Plant Ecology

基　　金：国家重点基础研究发展计划项目(2009CB421102);国家自然科学基金(41030105和31172247);国家自然科学青年基金(31201836);中国科学院战略性先导科技专项子课题(XDA050-70202);国家科技支撑课题专题(2011BAC09-B06-02)

摘　　要：为了研究高寒草原退化对土壤呼吸的影响,对三江源区不同退化程度的高寒草原土壤呼吸进行了测定,分析了土壤呼吸与生物量、土壤温度以及土壤湿度的相关性,结果表明:1)不同退化程度的高寒草原土壤呼吸均表现出一定的月动态,这种月动态在不同退化程度间各有不同。2)高寒草原在退化演替序列上生长季平均土壤呼吸速率呈先增加后降低的变化趋势,其中在中度退化程度下达到最高值((2.46±0.27)μmol·m–2·s–1),显著高于未退化((1.92±0.11)μmol·m–2·s–1)和重度退化((1.30±0.16)μmol·m–2·s–1)水平(p<0.01),与轻度退化((2.22±0.19)μmol·m–2·s–1)无显著差异(p>0.05),重度退化程度下呼吸速率显著低于其他退化水平(p<0.01)。3)地上生物量和土壤呼吸存在极显著线性正相关关系(p=0.004),而地下生物量与土壤呼吸的相关性不很显著(p=0.056)。4)除重度退化外,未退化、轻度退化和中度退化高寒草原土壤呼吸与土壤温度显著正相关;土壤呼吸与土壤湿度的二项式拟合方程在轻度退化程度下达到显著水平(p<0.05),而在未退化、中度退化和重度退化程度下均达到极显著水平(p<0.01)。Aims Soil respiration is a major way that CO2 is emitted into the atmosphere, and it is important in global change research. Our objective was to examine the effects of degradation on carbon flux in alpine grassland. Methods We measured soil respiration rates in alpine grassland under four degrees of degradation （no, light, moderate, and heavy degradation） using a LI-8100A open-circuit soil carbon flux measuring system. We analyzed the relationship between soil respiration and soil temperature, as well as between soil respiration and soil mois- ture. Important findings Soil respiration under each level of degradation showed a monthly dynamic, but it varied by degree of degradation. With an increase of degradation, average soil respiration of the growing season first in- creased and then decreased. The highest soil respiration occurred under the moderate level （（2.46 ± 0.27） mol·m^-2·s^-1）, which was significantly higher than under no degradation （（1.92 ± 0.11） mol·m^-2·s^-1） and heavy degradation （（1.30 ± 0.16） mol·m^-2·s^-1） （p 〈 0.01）. There was no significant difference between the moderate degradation and the light degradation （p 〉 0.05）. The respiration under heavy degradation was significantly lower than under the other degradation levels （p 〈 0.01）. There was a significant positive linear correlation between aboveground biomass and soil respiration （p = 0.004）, but not between soil respiration and underground biomass （p = 0.056）. There was a significant positive correlation between soil respiration and soil temperature at each level except heavy degradation. There were correlations between soil respiration and soil moisture （binomial fitting） with no degradation as well as moderate and heavy degradation （p 〈 0.05）, and it was significantly correlated with light degradation （p 〈 0.01）.

关 键 词：高寒草原 草地退化 土壤湿度 土壤呼吸 三江源区 温度 

分 类 号：S812[农业科学—草业科学]