中国生态农业学报2017，Vol.25Issue(10)：1413-1422,10.DOI:10.13930/j.cnki.cjea.170150
华北平原典型冬小麦农田生态系统 能量平衡与闭合研究
Energy balance and closure of typical winter wheat farmland ecosystem in the North China Plain
摘要
Abstract
The accurate quantification of energy and mass exchange between terrestrial ecosystem and the atmosphere is im-portant for water resources management and sustainable agricultural development. Energy balance closure is also a vital index for assessing the accuracy of measurements data and analyzing surface energy balance. In order to evaluate energy balance and energy closure in farmland ecosystems, the open eddy covariance system and total factor automatic weather station were used to observe continuous surface energy flux and conventional meteorological elements of typical winter wheat in farmland eco-systems in the North China Plain for the period 2013–2014. In the study, four typical growth stages (seeding, overwintering, jointing and grain-filling stages) were investigated for diurnal and annual variations in energy flux of winter wheat. Also the diurnal variations in Bowen ratio for four typical growth stages were calculated. The results showed that the trends in diurnal variations in net radiation and energy component of the four growing stages of winter wheat were unimodal in shape. The peak values of net radiation, sensible heat flux and latent heat flux were observed between 12:00 and 13:00. The maximum value of sensible heat flux was at 11:30 and the peak value of soil heat flux occurred between 14:00 and 15:00; which was about 1.00 hour later than sensible heat flux and latent heat flux. For annual variation, the trends in net radiation and latent heat flux were strongly consistent. The minimum values of net radiation and latent heat flux at overwintering stage were 114.51 W·m-2 and 13.47 W·m-2, respectively. However, sensible heat flux at overwintering stage was relatively higher than latent heat flux. Sen-sible heat flux and soil heat flux were respectively 33.61 W·m-2 and 13.05 W·m-2. The maximum values of net radiation and latent heat flux were observed at grain-filling stage, with respective values of 327.02 W·m-2and 116.56 W·m-2. After winter wheat harvest, sensible heat flux increased rapidly, while latent heat flux rapidly decreased. Energy closures of representative observation dates selected for the four growing stages were also good. The energy closure ratios were 0.49, 0.77, 0.81 and 0.76, respectively. The energy closure ratio was high in summer and relatively low in winter. Diurnal variations in Bowen ratio dur-ing the four growing stages had an inverted U-type curve. While Bowen ratio values for daytime were relatively stable, those for nighttime were negative and relatively unstable. The Bowen ratio curves agreed well with sensible heat flux curve. Bowen ratio was positive when sensible heat flux was positive and it increased with sensible heat flux. The maximum value of Bowen ratio at seeding stage (2.12) occurred at 14:00, while the maximum values of Bowen ratio at overwintering (1.48), jointing (0.31) and grain-filling stages (0.58) all occurred at 10:00. The results of the study set the basis for research on heat and water vapor fluxes in farmland ecosystems in the North China Plain.关键词
冬小麦/农田生态系统/能量平衡特征/涡度相关系统/能量闭合率/华北平原Key words
Winter wheat/Farmland ecosystem/Energy balance characteristics/Eddy covariance system/Energy closure ratio/North China Plain分类
农业科技引用本文复制引用
吴东星,李国栋,张茜..华北平原典型冬小麦农田生态系统 能量平衡与闭合研究[J].中国生态农业学报,2017,25(10):1413-1422,10.基金项目
国家自然科学基金项目(U1404401)、河南省高校科技创新团队支持计划项目(161RTSTHN012)、河南省高等学校青年骨干教师资助计划(2013GGJS-030)、河南大学资源与环境研究所项目(HD-ZHS-201403)和河南大学新兴交叉及特色学科培育项目(XXJC20140003)资助 The study was funded by the National Natural Science Foundation of China (U1404401), Henan Province University Scientific and Techno-logical Innovation Team Support Project (161RTSTHN012), the Foundation of Henan Provincial Youth Backbone Teachers (2013GGJS-030), the Project of Henan University Resource and Environment Research Institute (HD-ZHS-201403) and the New Interdisciplinary and Charac-teristic Subject Cultivation Project of Henan University (XXJC20140003). （U1404401）
