| 田世丽,竺夏英,潘月鹏,谢雨竹,周焱博,张国忠.华北玉米农田大气/植被界面氨气和铵盐动态变化研究[J].农业环境科学学报,2018,37(10):2327-2333. |
| 华北玉米农田大气/植被界面氨气和铵盐动态变化研究 |
| Dynamics of ammonia and ammonium at the atmosphere-vegetation interface over a selected maize farmland in the North China Plains |
| 投稿时间：2017-12-12 |
| DOI：10.11654/jaes.2017-1703 |
| 中文关键词: 氨气 铵盐 植被冠层 农田 玉米叶片 大气氮沉降 |
| 英文关键词: ammonia ammonium vegetation canopy farmland maize leaf atmospheric nitrogen deposition |
| 基金项目:国家自然科学基金项目（41405144）；国家重点研发计划专项（2017YFC0210100）；国家重点基础研究发展规划项目（2012CB417100） |
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| 中文摘要: |
| 为系统研究大气/植被界面还原性氮（氨气和铵盐，NHx）的动态变化，选择华北典型玉米农田生态系统，于2016年8月和9月开展了2次综合观测实验，同步采集并测量了植被冠层大气中氨气和铵盐浓度（气溶胶和降水）、玉米叶片和土壤中铵盐含量。结果表明：实验期间（玉米抽穗期和花粒期），植被冠层氨气和铵盐浓度的平均值分别为30.6±6.8 μg·m-3和5.9±3.3 μg·m-3，变化范围分别为21.1~37.6 μg·m-3和2.1~8.0 μg·m-3；降水过程造成植被冠层的气溶胶铵盐浓度下降了75%，这一比例（被降水湿清除的效率）显著高于氨气。玉米叶片中铵盐含量从植株顶端到底部呈现下降趋势，变化范围为0.17~0.25 mg·g-1（抽穗期）和0.74~1.20 mg·g-1（花粒期），且呈现随温度升高而升高的日变化特征。抽穗期植株氨气补偿点为1.9±1.4 μg·m-3，远低于大气氨气浓度31.4±4.8 μg· m-3；花粒期植株氨气补偿点52.0±30.7 μg·m-3，高于大气氨气浓度29.3±11.7 μg·m-3。8月10-13日玉米抽穗期，大气活性氮通过降水、气体和气溶胶3种途径输入到农田的总量约25 mg N·m-2·d-1，是农田土壤和作物可利用氮的重要来源。农田氮管理中需要充分考虑植被与冠层大气氨的交换过程。 |
| 英文摘要: |
| The exchange and variation of reduced nitrogen[gaseous ammonia (NH3) and particulate ammonium (NH4+), i.e., NHx] at the atmosphere-vegetation interface of a typical maize farmland ecosystem in north China were studied. Atmospheric concentrations of NH3 and NH4+ above the vegetation canopy, as well as NH4+ concentrations in maize leaves and soil samples, were simultaneously measured. The results showed that atmospheric concentrations of NH3 and NH4+ ranged from 21.1 to 37.6 μg·m-3 and from 2.1 to 8.0 μg·m-3, respectively. The removal efficiency of NH4+ (75%) by precipitation was much higher than that of NH3. The NH4+ content in maize leaves decreased from the top to the bottom of the maize plant, and tended to be higher as temperature increased. During the heading period, the average NH3 compensation point of leaves was 1.9±1.4 μg·m-3, which was lower than the canopy NH3 concentration (31.4±4.8 μg·m-3). Conversely, the average NH3 compensation point of leaves was 52.0±30.7 μg·m-3, which was higher than the canopy NH3 concentration (29.3±11.7 μg·m-3) during the anthesis maturity period. During the observation period between August 10 and 13, atmospheric reactive nitrogen deposition into the farmland via precipitation, gas, and aerosol was about 25 mg N·m-2·d-1, which was an important source of soil nitrogen and crop available nitrogen. The NH3 exchange between the atmosphere and plants should be considered in nitrogen management in intensive Chinese agricultural systems. |
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