摘要:旨在了解农田CO₂浓度长期动态变化特征、趋势、浓度增量分布模式等，收集了2007-2018年中国气象局固城生态与农业气象试验站开路式涡相关CO₂浓度观测数据。研究了华北平原农田CO₂浓度的年际、年内、昼夜和CO₂通量等动态变化特征，对比分析了华北平原农田CO₂浓度与城市站和大气本底站CO₂浓度变化趋势及差异。结果表明，近十多年来华北平原农田CO₂年平均浓度显著升高31.0 μmol/mol（r=0.263，P < 0.01），年均增幅（2.58 μmol/mol）与全球和瓦里关本底站大气CO₂浓度增幅接近，但农田CO₂浓度年际和年内季节变化波动巨大，日平均浓度和逐时平均浓度标准差分别为33.7、33.5 μmol/mol。夜间CO₂平均浓度395.8 μmol/mol，比白天高36.2 μmol/mol（10.1%），8月最高差值达到74.4 μmol/mol（20.6%）。在作物生长季节，5月和8-9月白天CO₂浓度出现的两个谷值准确地对应了CO₂通量动态变化的两个峰值，表明4-9月昼间CO₂浓度和通量动态变化很好地反映了华北平原冬小麦和夏玉米生长过程、农事活动和农田碳交换的关系。农田CO₂浓度动态变化与城市、湿地和大气本底站的变化特征不同，表明其动态变化的形成机制有差异。农田CO₂浓度昼夜及季节变化特征为研究和评估CO₂浓度升高影响作物生长和产量提供指导依据。



Abstract:The atmospheric carbon dioxide (CO₂) is the most important greenhouse gas in the global warming. Many researches concerning the CO₂ concentration enrichments impact on crop growth and product had been carried out based on the change of CO₂ concentration which observed from background station instead of from farmland station, yet the crop grew in farmland near to the village and town. In addition, few study paid attention to the variation of atmospheric CO₂ concentration over the farmland despite many researches focused on carbon cycle and carbon exchange. In order to know the long-term dynamics, trends and increment distributions of CO₂ concentration in farmland, we collected the data of CO₂ concentration observation of open pass eddy covariance system during 2007-2018 over the farmland in Gucheng Ecological and Agrometeorological Experimental Station of China Meteorological Administration. After data quality control and statistical analysis, we studied the dynamic characteristics of CO₂ concentration in farmland of North China Plain, such as inter-annual, intra-annual, diurnal and CO₂ flux, and compared the differences of CO₂ concentration and the trends in farmland of North China Plain with those in urban station and atmospheric background station. The results showed that the annual average concentration of CO₂ in the farmland of North China Plain had increased significantly from 361 to 392 μmol/mol in past twelve years (r=0.263, P < 0.01), with the average annual increment of 2.58 μmol/mol of CO₂ concentration, which close to that in global and Waliguan background station of China. However, the inter-annual and intra-annual variations of CO₂ concentration in the farmland fluctuated greatly with the standard deviation (SD) of 33.7 and 33.5 μmol/mol respectively. The average concentration of CO₂ in the night was 395.8 μmol/mol, higher 36.2 μmol/mol (10.1%) than that in the day in all the months, with the highest difference of 74.4 μmol/mol (20.6%) in August. In crop growth season, the two valley values of diurnal CO₂ concentration accurately matched the two peaks of the dynamic change of the CO₂ flux in May and August to September, which indicate that the dynamic changes of daily average CO₂ concentration and flux in day and night from April-September well reflected the relationships between the growth processes of winter wheat and summer maize, agricultural activities and carbon exchanges of farmland in the North China Plain. The dynamic change of CO₂ concentration in farmland was different from that in cities, wetlands and atmospheric background stations, suggesting the different formation mechanisms of CO₂ dynamic change. The characteristics of diurnal and night and seasonal variation of CO₂ concentration in farmland can provide guidance for studying and evaluating the effects of elevated CO₂ concentration on crop growth and yield.





PDF全文下载地址:

https://www.ecologica.cn/stxb/article/pdf/stxb201906201310