西南喀斯特地区轮作旱地土壤CO2通量

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 西南喀斯特地区轮作旱地土壤CO2通量 DOI: 10.5846/stxb201206160864 作者: 作者单位: 中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室,中国科学院地球化学研究所 环境地球化学国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然基金(40872212);中国科学院战略性科技先导专项(碳专项);贵州省农业攻关计划项目(黔科合NY字[2011]3079号) CO2 flux in the upland field with corn-rapeseed rotation in the karst area of southwest China Author: Affiliation: State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laborat ory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science,State Key Laboratory of Environmental Geochemistry,Institution of Geochemistry,Chinese Academy of Science Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:中国已承诺大幅降低单位GDP碳排放,农业正面临固碳减排的重任。西南喀斯特地区环境独特,旱地面积占据优势比例,土壤碳循环认识亟待加强。以贵州省开阳县玉米-油菜轮作旱地为研究对象,采用密闭箱-气相色谱法对整个轮作期土壤CO2释放通量进行了观测研究,结果表明:(1)整个轮作期旱地均表现为CO2的释放源。其中油菜生长季土壤CO2通量为(178.8±104.8) mg CO2·m-2·h-1,玉米生长季为(403.0±178.8) mg CO2·m-2·h-1,全年平均通量为(271.1±176.4) mg CO2·m-2·h-1, 高于纬度较高地区的农田以及同纬度的次生林和松林;(2)CO2通量日变化同温度呈现显著正相关关系,季节变化与温度呈现显著指数正相关关系,并受土壤湿度的影响,基于大气温度计算得出的Q10为2.02,高于同纬度松林以及低纬度的常绿阔叶林;(3)CO2通量与土壤pH存在显著线性正相关关系,显示出土壤pH是研究区旱地土壤呼吸影响因子之一。 Abstract:Farmland ecosystems constitute great carbon sources in terrestrial ecosystems and have important influence on the global carbon cycle. As China has promised to reduce carbon emission significantly, China's agriculture is facing the challenge of carbon sequestration and reduction of carbon emission. As the environment in karst area of southwest China is unique and upland field covers a large scale, further research is badly needed to quantify diurnal and seasonal variations of soil CO2 flux, and to investigate the effects of temperature, soil water content and soil properties on soil CO2 flux. Taking upland field with corn-rapeseed rotation in Kaiyang country of Guizhou province as our study subject, we used static enclosed chamber coupled with GC to observe the soil CO2 flux of all the rotation period. Continuous measurements of soil temperature and moisture were conducted together with several other physical and chemical properties of the soil. It was found that the upland with corn-rapeseed rotation performed as the source of CO2. The mean CO2 flux was (178.8±104.8) mg CO2·m-2·h-1 in the rapeseed growing season, (403.0±178.8) mg CO2·m-2·h-1 in the maize growing season, and (271.09±176.37) mg CO2·m-2·h-1 for the whole rotation period. These values are in the upper part of the range of published soil-surface CO2 flux date. There were significant positive correlations between soil CO2 flux and temperature in both diurnal changes and seasonal fluctuations. The diurnal fluctuations of CO2 flux showed similar patterns and fluctuated from minimum around 12 pm to maximum at 1 pm to 3 pm. For the seasonal variations, soil CO2 flux was positively correlated with temperature in the whole crop rotation with the minimum value of 31.10 mg CO2·m-2·h-1 in February and the maximum value of 665.46 mg CO2·m-2·h-1 in August. An exponential function provided the best fit for describing the relationship between seasonal soil CO2 flux and temperature for the whole crop rotation, with the higher correlation found with the soil temperature at 5 cm depth. About 86.7% of the seasonal soil CO2 flux variations can be explained by air temperature, while 80.5% by the soil temperature at 5 cm depth. The results showed that the temperature was the determinant factor controlling temporal variation of soil CO2 flux both diurnally and seasonally. The correlations between soil CO2 flux and soil water content differed for the two kinds of crops. For the rapeseed growing season when soil water content was relatively high, the soil CO2 flux and soil water content had a positive correlation. While there was a negative relationship between soil CO2 flux and soil water content for the maize growing season. Both the relationships were not statistically significant which indicated that the soil water content was not the determinant factor for the soil CO2 flux changes. The Q10 value was calculated as 2.02 based on the atmospheric temperature, higher than pinewood at similar latitudes and evergreen broad-leaved forest at lower latitudes. This meant that the upland field corresponded more sensitively to the temperature changes. The significant positive correlation between soil CO2 flux and soil pH indicated that the soil CO2 flux was influenced by several parameters at the same time. 参考文献 相似文献 引证文献