| 温带荒漠中温度和土壤水分对土壤呼吸的影响 |
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| 引用本文： | 张丽华,陈亚宁,赵锐锋,李卫红.温带荒漠中温度和土壤水分对土壤呼吸的影响[J].植物生态学报,2009,33(5):936-949. |
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| 作者姓名： | 张丽华 陈亚宁 赵锐锋 李卫红 |
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| 作者单位： | (中国科学院绿洲生态与荒漠环境重点实验室, 中国科学院新疆生态与地理研究所,乌鲁木齐 830011) |
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| 基金项目： | 国家科技支撑计划项目，中国科学院研究生科学与社会实践资助专项 |
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| 摘 要： | 荒漠对气候变化具有高度敏感性, 深刻认识和量化非生物因子对荒漠生态系统土壤呼吸的影响具有重要意义。采用自动CO2通量系统(Li-8100)监测了梭梭(Haloxylon ammodendron)、假木贼(Anabasis aphylla)和盐穗木(Halostachys caspica)群落生长季土壤呼吸及温度、土壤含水量等, 深入分析了水热因子对土壤呼吸的影响。土壤呼吸具有不对称的日格局, 最小值出现在8:00, 最大值在12:00~14:00。土壤呼吸的季节格局与气温变化基本同步, 最小值在生长季末期(10月), 最大值在生长季中期(6~7月)。梭梭、假木贼和盐穗木群落生长季平均土壤呼吸速率分别为0.76、0.52和0.46 μmol CO2·m–2·s–1。气温对假木贼(51%)和盐穗木群落(65%)土壤呼吸季节变化的解释率高于梭梭(35%)。梭梭、假木贼和盐穗木群落土壤呼吸温度敏感性(Q10)逐渐增大, 基础呼吸速率(R10)逐渐减小。剔除温度影响后, 梭梭、假木贼群落土壤呼吸与土壤含水量呈显著的幂二次方函数关系, 盐穗木群落两者关系却明显减弱, 未达到显著水平。气温、土壤含水量的二元方程均能解释群落土壤呼吸大部分的时间变异: 梭梭群落71%~93%、假木贼群落79%~82%、盐穗木群落70%~80%。人工模拟降水后土壤呼吸速率表现出降水后10 min减小、180 min时明显增加、达到最大值后再次衰减的现象。5和2.5 mm降水处理下的土壤呼吸速率最大值和其后的递减值高于对照处理, 土壤呼吸增加、达到峰值和其后递减过程与5 cm土壤温度变化基本同步。
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| 关 键 词： | 土壤呼吸 温度 土壤含水量 人工降水 荒漠 干旱区 |
IMPACT OF TEMPERATURE AND SOIL WATER CONTENT ON SOIL RESPIRATION IN TEMPERATE DESERTS, CHINA |
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| ZHANG Li-Hua,CHEN Ya-Ning,ZHAO Rui-Feng,LI Wei-Hong.IMPACT OF TEMPERATURE AND SOIL WATER CONTENT ON SOIL RESPIRATION IN TEMPERATE DESERTS, CHINA[J].Acta Phytoecologica Sinica,2009,33(5):936-949. |
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| Authors: | ZHANG Li-Hua CHEN Ya-Ning ZHAO Rui-Feng LI Wei-Hong |
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| Affiliation: | Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Ürümqi 830011, China |
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| Abstract: | Aims Our objective was to determine the impact of temperature and soil water content on soil respiration in Haloxylon ammodendron, Anabasis aphylla and Halostachys caspica desert communities. Methods We measured soil respiration in the 2005 and 2006 growing seasons using an automated CO2 efflux system (Li-Cor 8100). Air temperature (at 50 cm in height) and soil temperature (every 5 cm from 0 to 50 cm depth) were monitored at three points adjacent to the chamber using a digital ther-mometer at each site. Gravimetric soil moisture at 0–5, 5–15, 15–30, and 30–50 cm depths at three points was measured using the oven-drying method at 105 °C for 48 h. Water was added for artificial precipitation using plastic watering cans. Important findings Soil respiration showed an asymmetric daytime pattern, with the minimum at 8:00 and the maximum at 12:00–14:00. The seasonal variation of soil respiration was characterized by a minimum in October and a maximum in June or July, which generally followed that of air temperature. The mean soil respiration rate in the growing season was 0.76, 0.52 and 0.46 μmol CO2·m–2·s–1 in Haloxylon ammodendron, Anabasis aphylla and Halostachys caspica communities, respectively. Air temperature explained >35%, 51% and 65% of seasonal variations of soil respiration in Haloxylon ammodendron, Anabasis aphylla and Halostachys caspica communities, respectively. Q10 values increased in Haloxylon ammodendron (1.35), Anabasis aphylla (1.41) and Halostachys caspica (1.52) communi-ties, and R10 decreased 0.45, 0.30 and 0.22 μmol CO2·m–2·s–1 in each site, respectively. Significant power and quadratic relationships existed between normalized soil respiration and soil water content in the Haloxylon ammodendron and Anabasis aphylla communities, but not in the Halostachys caspica community. Two-dimensional equations based on temperature and soil water content explained most of temporal variations of soil respiration: 71%–93% in Haloxylon ammodendron, 79%–82% in Anabasis aphylla and 70%–80% in Halostachys caspica. Following artificial precipitation, the rate of soil respira-tion decreased, increased and then quickly decreased again, a pattern consistent with changes in soil temperature. |
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| Keywords: | soil respiration temperature soil water content artificial precipitation desert arid region |
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