| 温度和生物因子对农田生态系统呼吸的影响——以华北平原冬小麦-夏玉米复种农田生态系统为例 |
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| 引用本文： | 郑泽梅,于贵瑞,温学发,张雷明,孙晓敏.温度和生物因子对农田生态系统呼吸的影响——以华北平原冬小麦-夏玉米复种农田生态系统为例[J].资源科学,2009,31(4). |
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| 作者姓名： | 郑泽梅 于贵瑞 温学发 张雷明 孙晓敏 |
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| 作者单位： | 1. 中国科学院地理科学与资源研究所生态系统观测与模拟重点实验室CERN综合研究中心,北京100101;中国科学院研究生院,北京100049
2. 中国科学院地理科学与资源研究所生态系统观测与模拟重点实验室CERN综合研究中心,北京,100101 |
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| 基金项目： | nowledge Innovation Program of the Chinese Academy of Sciences，国家自然科学基金，International Partnership Project of CAS |
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| 摘 要： | 生态系统呼吸在陆地生态系统碳循环中占有重要地位,是碳循环中仅次于生态系统总初级生产力的第二大通量组分.除温度和水分外,生物因子对生态系统呼吸也有着重要的影响.生物因子往往与温度、水分有着相似的季节变化,并且温度还对这些因子有重要的影响,这加深了探讨生物因子对生态系统呼吸影响的难度.复种农田生态系统中生物因子与气象因子季节变化的非同步性为探讨生物因素对生态系统呼吸时间变异的影响提供了有利条件.利用华北平原冬小麦一夏玉米复种农田LAI的季节动态与温度的季节动态存在非同步性这一天然试验条件,本研究通过该农田生态系统连续两年的涡度相关通量观测数据,分析了温度和生物因子对该农田生态系统呼吸季节及年际变化的影响.结果表明,在冬小麦和夏玉米的各个生育阶段,其夜间生态系统呼吸都受到土壤温度的影响,但是这种影响在作物不同的生育阶段有所差异,尤其当土壤温度与叶面积指数(LAI)的季节变化非同步时,LAI会改变土壤温度对生态系统呼吸的控制.基于直线回归方程,LAT能分别解释2003年和2004年冬小麦生态系统参考呼吸(10℃下的生态系统呼吸速率)变异的97%和74%,能分别解释夏玉米生态系统参考呼吸变异的85%和42%.华北平原冬小麦一夏玉米复种农田的生态系统呼吸呈"双峰"季节动态模式,且与生态系统总初级生产力及LAI的季节动态模式相一致,两次峰值分别出现在冬小麦的LAI和夏玉米的LAI达到最大时.冬小麦农田生态系统呼吸的最大值在2003年和2004年分别为6.6 gC/(m2·d)和5.5 gC/(m2·d),夏玉米农田生态系统呼吸的最大值在2003年和2004年分别为7.7 gC/(m2·d)和6.9 gC/(m2·d).冬小麦农田生态系统在2003年和2004年2个生育期的总呼吸量分别为402 gC/m2(累计220天)和486 gC/m2(累计232天).夏玉米农田生态系统在2003年和2004年两个生育期的总呼吸量分别为557 gC/m2(累计131天)和48l gC/m2(累计107天).冬小麦及夏玉米生育期生态系统呼吸的年际差异受土壤温度和受LAI影响的生态系统总初级生产力的协同作用控制.冬小麦秸秆还田引起的生态系统呼吸底物的增加以及夏季降雨对土壤湿度的改善都促进了夏玉米生长前期生态系 .统CO:排放量的增加.相对于自然生态系统,农田生态系统受到更多的管理措施的影响,因此在未来的研究中,应加强农业管理措施以及人类活动对农田生态系统呼吸影响的研究.
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| 关 键 词： | 农田生态系统 冬小麦-夏玉米复种农田 生态系统呼吸 土壤温度 华北平原 |
Temperature and Biotic Factor Control the Seasonal and Interannual Variations of Ecosystem Respiration .A case study of Winter Wheat-summer Maize Double Agroecosystem |
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| ZHENG Zemei,YU Guirui,WEN Xuefa,ZHANG Leiming,SUN Xiaomin.Temperature and Biotic Factor Control the Seasonal and Interannual Variations of Ecosystem Respiration .A case study of Winter Wheat-summer Maize Double Agroecosystem[J].Resources Science,2009,31(4). |
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| Authors: | ZHENG Zemei YU Guirui WEN Xuefa ZHANG Leiming SUN Xiaomin |
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| Abstract: | The ecosystem respiration (Re),following gross primary productivity, is the second largest carbon flux in global carbon cycle. More and more studies indicate that biotic factors (e.g. LAI),besides temperature and moisture, are expected as key factors in determining the seasonal distribution of Re, which reflects the ecophysiological process of plant such as capacity of photosynthesis and photosynthetic substrate supply for R.. Such influence, however,is difficult to be quantified due to the in-phase of seasonal patterns of biotic factors and temperature, as well as the important effect of temperature on biotic factors. The asynchronism in the seasonal distributions of temperature and LAI of winter wheat-summer maize double agroecosystem in the North China Plain enables us to study the influences of biotic factors on Re. In this study,the influences of temperature and biotic factors on the seasonal and interannual variations of ecosystem respiration Re of a winter wheat-summer maize double agroecosystem were analyzed by using 2 years' continuous data from eddy covariance measurements. The results showed that nighttime Re was influenced by soil temperature across different growing periods of winter wheat and summer maize, but such influences were altered when seasonal trend of LAI was asynchronous with temperature. LAI explained 97% and 74% of the variability in Re at a given soil temperature (Rref) of winter wheat and explained 85% and 42% of the variability of R(ref) of summer maize in 2003 and 2004, respectively. The seasonal trend of daily R, was highly correlated with LAI and gross ecosystem productivity,The cumulative Re of winter wheat during the two growth periods in 2003 and 2004 were respectively 402 gC/cm2 and 486 gC/cm2,and for summer maize being 557 gC/cm2 and 481gC/cm2,respectively. The interannual variation of Re was closely correlated with the variations in temperature and photosynthetic substrate supply controlled by LAI. More straw of winter wheat returned into soil and frequent precipitation in summer promoted Re of summer maize. Compared to natural ecosystem,agroecosystem is affected more by cropping system and field managements, thus, the effect of field management and human activity on Re and carbon budget in agroecosystem is a research focus in the future researches. |
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| Keywords: | Agroecosystem Biotic Ecosystem respiration Soil temperature The North China Plain |
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