【作者】 陈宇；

【导师】 许小燕； 张宝忠；

【作者基本信息】 合肥工业大学 ， 水利工程（专业学位）， 2019， 硕士

【摘要】 在全球气候变化的背景下,对大气和陆地生态系统之间碳循环规律的研究已经成为了当今科学界的热点,其中农田生态系统作为受人类活动影响最大的生态系统,对整个陆地生态系统的碳循环做出了突出的贡献。因此研究农田生态系统的碳通量规律,对进一步认识陆地生态系统碳循环具有重要意义。本文采用涡度相关技术,对我国皖南丘陵地区的玉米农田生态系统碳通量进行了持续的观测,并分析了碳通量的变化规律和控制机理,明确了其碳源/汇功能的时间分布特征,另外还探究了玉米地的固碳效率变化规律,最后对两个主要的碳通量模型进行了验证和比选,明确了在不同条件下模型对模拟玉米地碳通量的适用性。取得的主要研究成果有:(1)玉米地在夜间为碳源,白天为碳汇,夏玉米在前中期为碳源,后期为碳汇,春玉米在整个生育期均为碳汇;玉米碳通量的日内变化特征在阴天和生育前期晴天表现为夜间平稳,白天先下降再上升的“U”型单峰曲线,而在生育后期晴天表现为中午出现短暂回升现象的“W”型双峰曲线,且高温条件下玉米地具有较强的碳源功能。(2)玉米地固碳效率日内变化呈先上升再保持稳定最后下降的梯形特征,夏玉米在前中期(拔节期、抽穗期)的固碳效率低于春玉米,后期(灌浆期、成熟期)高于春玉米。(3)玉米地碳通量在小时尺度上受净辐射影响最大,在日尺度上春玉米受饱和水汽压差影响最大,夏玉米受气温影响最大。(4)SMPT-SB模型在玉米地整个生育期的模拟效果优于CROP-C模型,而在日内的模拟效果则各有优劣:SMPT-SB模型更适合在夜间模拟玉米地的碳源功能;CROP-C模型更适合在白天模拟玉米地的碳汇功能。更多还原

【Abstract】 In the context of global climate change,carbon flux cycle between atmospheric and terrestrial ecosystems has become a research focus in scientific community.Farmland ecosystems are the ecosystems most affected by human activities and have made outstanding contributions to the carbon cycle of entire terrestrial ecosystem.The carbon cycle has made a significant contribution.Therefore,researching the carbon flux of farmland ecosystems is of great significance for further understanding of the carbon cycle of terrestrial ecosystems.The eddy covariance technique was used to observe the carbon flux of maize farmland ecosystem in the hilly area of southern Anhui Province.And its variation and control mechanism of carbon flux were analyzed,and the time distribution characteristics of carbon source/sink properties were clarified.The change of carbon fixation efficiency of maize field was also explored.Finally,two main carbon flux models were validated and compared,and the applicability of the model to the simulated maize field carbon flux under different conditions was clarified.The main results are here:(1)Maize field is a carbon source at night,carbon sink during the day.Summer maize is a carbon source in the early and middle stages,and carbon sink in the later stage.Spring maize is carbon sink throughout the growth period.The intraday variation of maize carbon flux is characterized by a “U”-type single-peak curve that is stable at night,falling first and then rising during the daytime in cloudy and sunny day of early stage,or a “W”-type double-peak curve with a short-term rebound at noon in sunny day of later stage.In addition,maize field has strong carbon source properties under high temperature conditions.(2)The intraday variation of carbon fixation efficiency of maize field increased first and then remained stable and finally decreased.The carbon fixation efficiency of summer maize in the early and middle stages(jointing stage,heading stage)was lower than that of spring maize,and in the later stage(filling stage,maturity stage)was higher than that of spring maize.(3)The carbon flux of maize field is most affected by net radiation on the hourly scale.On the daily scale,spring maize is most affected by the vapor pressure deficit,and summer maize is most affected by the temperature.(4)SMPT-SB model has better simulation effect than the CROP-C model in the whole growth period of maize field,but the simulation effect in the day has its advantages and disadvantages: SMPT-SB model is more suitable for simulating the carbon source function of maize field at night;CROP-C model is more suitable for simulating the carbon sink function of maize fields during the day.更多还原