| 钟光迪,任羡,潘珊珊,张翀,巨晓棠.改进密闭室抽气法以准确定量旱地土壤氨挥发[J].农业环境科学学报,2024,43(10):2434-2442. |
| 改进密闭室抽气法以准确定量旱地土壤氨挥发 |
| Improving dynamic chamber method to accurate determine ammonia volatilization from upland soils |
| 投稿时间：2024-04-28 |
| DOI：10.11654/jaes.2024-0370 |
| 中文关键词: 密闭室抽气法 大气背景氨 土壤氨挥发 华北平原 冬小麦-夏玉米轮作 |
| 英文关键词: dynamic chamber method atmospheric ammonia soil ammonia volatilization north China plain winter wheat-summer maize rotation |
| 基金项目:海南省自然科学基金项目(422RC597);国家自然科学基金项目(42207348);海南省重大科技计划项目(ZDKJ2021008);海南大学启动经费[KYQD(ZR)-20098,KYQD(ZR)-21028] |
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| 中文摘要: |
| 密闭室抽气法被认为是定量土壤NH3挥发较为可靠的方法，具有灵敏度高且成本低的优点。然而，大部分研究忽略了密闭室抽气法大气进气口NH3浓度，可能会高估土壤NH3挥发量，目前尚缺乏相关定量研究。本研究以华北冬小麦-夏玉米轮作为对象，对比分析了2019——2021年间冬小麦基肥（2次）、追肥（1次）、夏玉米四叶肥（2次）、夏玉米十叶肥（2次）共7次施肥后，改进密闭室抽气法前后测定农田土壤NH3挥发的结果。改进前为包含大气背景NH3的测定方法，为常规测定方法；改进后为扣除大气背景NH3的测定方法，通过在田间加装3套采集距地面2.5 m高度大气的装置实现。结果表明：改进后的NH3挥发通量（以N计）比改进前低0~0.23 kg·hm-2·d-1 （0%~100%），平均值为0.06 kg·hm-2·d-1 （33%），且37%的样本存在显著性差异（P<0.05，n=931）。改进后的NH3挥发累积量比改进前低0.53~2.66 kg·hm-2 （3%~53%），平均值为1.15 kg·hm-2 （29%），且47%的样本存在显著性差异（P<0.05，n=49）。改进前后NH3挥发量（包括通量和累积量）存在显著差异的样本占比随着NH3挥发量降低而升高。回归分析表明，改进前的NH3挥发累积排放量可以用算式校正得到真实的NH3累积排放量，校正式为y=0.94x-0.78（R2=0.99，P<0.01，n=49），其中y和x分别为校正后和校正前的NH3挥发累积量，该算式可应用于华北土壤-作物体系NH3挥发累积量的校正。综上，利用抽气法定量农田土壤NH3挥发需要扣除大气背景NH3以得到准确的测定结果，对于未扣除大气背景的旱地NH3挥发累积量，可采用校正算式进行校正。 |
| 英文摘要: |
| The dynamic chamber method is considered a reliable approach to quantify soil ammonia（NH3） volatilization, with the advantages of high sensitivity and low cost. However, most researchers often ignore the atmospheric NH 3 concentration from the inlet of the chamber, which may overestimate soil NH3 volatilization. However, the relevant quantitative studies are still lacking. This study took the winter wheat-summer maize rotation system in the North China Plain as an objective, compared NH3 volatilization measured before and after improvements of the dynamic chamber method using the data of seven fertilization events, which included basal fertilization and topdressing in winter wheat and four-and ten-leaf fertilization in summer maize. Before improvements, the obtained NH 3 fluxes include atmospheric NH3 concentration, representing the conventional approach. After improvements, the atmospheric NH3 was excluded from the NH3 fluxes by installing three sets of devices for atmospheric collection at a height of 2.5 meters above ground. The results showed that the improved method had 0-0.23 kg·hm-2·d-1 （0%-100%）lower NH3 fluxes（calculated on nitrogen）than before, with an average of 0.06 kg·hm-2·d-1 （33%）, and 37% of the samples showed significant differences（P<0.05, n=931）. Moreover, the improved method had 0.53-2.66 kg·hm-2（3%-53%）lower cumulative NH3 emissions than before, with an average of 1.15 kg·hm-2·d-1（29%）, and 47% of the samples showed significant differences（P<0.05, n=49）. The proportion of samples with significant differences in NH3 emissions between before and after improvements increased as NH3 emissions decreased. Regression analysis revealed that the cumulative NH3 emissions before improvements could be calibrated by the equation of y=0.94x-0.78（R2=0.99, P<0.01, n=49）, thus to obtain the real NH3 cumulative emissions, where y and x represent the cumulative NH3 emissions after and before calibration, respectively. This equation could be applied to the soil-crop systems in the North China Plain. In conclusion, we must exclude the atmospheric NH3 when using the dynamic chamber method to quantify soil NH3 volatilization. For cumulative NH3 emissions including the atmospheric NH3, the equation derived from this study can be used for calibration. |
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