引用本文:田玉华,曾 科,姚元林,尹 斌.基于不同监测方法的太湖地区水稻穗肥期氨排放研究[J].土壤学报,2019,56(3):693-702.
TIAN Yuhua,ZENG Ke,YAO Yuanlin,YIN Bin.Ammonia Emission Following Fertilization at Booting Stage of Rice Crop in Taihu Lake Region relative to Monitoring Techniques[J].Acta Pedologica Sinica,2019,56(3):693-702
【打印本页】   【HTML】   【下载PDF全文】   查看/发表评论  【EndNote】   【RefMan】   【BibTex】
←前一篇|后一篇→ 过刊浏览    高级检索
本文已被:浏览 80次   下载 112 本文二维码信息
码上扫一扫!
分享到: 微信 更多
基于不同监测方法的太湖地区水稻穗肥期氨排放研究
田玉华1, 曾 科1, 姚元林2, 尹 斌1
1.土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所);2.南京信息工程大学应用气象学院
摘要:
稻田追肥撒施氮肥易引起氨挥发损失,水稻穗肥撒施后稻田生态系统的氨排放仍未明确。在太湖地区水稻穗肥施用后同步采用微气象学法(IHF)、密闭室抽气法和通气法对稻田氨排放进行监测。结果表明,三种方法监测的稻田氨排放动态变化特征一致,施肥后第2天达峰值,至第5天不再有明显排放,田面水NH4+-N浓度与氨排放变化规律一致;IHF法监测稻田冠层上方氨排放量为5.45 kg·hm-2(以N计,下同),占施氮量的6.73%;密闭室抽气法监测稻田土-水表面氨排量为17.4 kg·hm-2, 占施氮量的21.5%,土-水表面氨排放与气温直线相关,适宜抽气时间为8:00 ~ 9:00和16:00 ~ 17:00,密闭室抽气法测定的为土-水表面氨排放潜力,未考虑冠层对挥发氨的捕获,导致穗肥期氨排放高估,该法适宜比较不同处理的氨排放潜力,今后需统一抽气室规格和抽气量;通气法监测土-水表面氨排放结果低于密闭室抽气法。评价稻田穗肥氨排放应以IHF法监测的冠层上方的排放量为准。
关键词:  氨排放  微气象学法  密闭室抽气法  通气法  孕穗期  水稻冠层
DOI:10.11766/trxb201806280349
分类号:
基金项目:国家重点研发计划项目(2016YFC0207906)资助
Ammonia Emission Following Fertilization at Booting Stage of Rice Crop in Taihu Lake Region relative to Monitoring Techniques
TIAN Yuhua1, ZENG Ke1, YAO Yuanlin2, YIN Bin1
1.State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences;2.School of Applied Meteorology, Nanjing University of Information Science & Technology
Abstract:
【Objective】 There is a long history, more than 400 years, of fertilization at booting stage of single cropping rice (Oryza sativa L.) in the Taihu Lake region. Historical records show it started in the late Ming Dynasty. Fertilization at the booting stage of rice can effectively improve yield and quality of rice. However, ammonia volatilization is liable to occur when top-dressing fertilizer is broadcasted onto paddy fields. Ammonia emitted from agricultural fields brings about adverse effects on the air and water environment, such as smog and eutrophication. How ammonia emits from paddy ecosystems after fertilization at the booting stage of rice is still not clear. 【Method】Field measurement of ammonia emissions from paddy fields at the booting stage of single cropping rice was conducted in the rice season of 2017 in the Taihu Lake region, using simultaneously three different techniques different in monitoring principle, including micrometeorological mass-balance integrated horizontal flux (IHF), dynamic chamber technique and static chamber technique. For the IHF technique, five layers of passive flux ammonia samplers were placed at a set interval around a mast in the center of circular plots (20-m radius) above the soil-water surface, and this apparatus did not need simultaneous measurement of ammonia concentration and wind speed. For the dynamic technique, air exchange rate of 17 times per minute was adopted, and NH4+-N concentration and pH in the floodwater on the surface of the paddy field was measured after surface application of urea. 【Result】Results show that dynamics of the daily ammonia emissions monitored with the three different techniques were similar in feature. Ammonia emission peaked on the second day after surface application of urea and continued till the 5th day when it stopped. The dynamics of the NH4+-N concentration in the surface floodwater and ammonia emission varied similarly. Monitoring with the IHF technique showed that cumulative ammonia (NH3-N) emission above the rice canopy was 5.45 kg·hm-2, accounting for 6.73% of the applied nitrogen. Monitoring with the dynamic chamber technique showed that ammonia emission from soil-water surface was 17.4 kg·hm-2, accounting for 21.5% of the applied nitrogen, and that ammonia emission from the soil-water surface and ammonia emission flux were linearly related with air temperature. And monitoring with the dynamic chamber technique showed that the optimal timing for air sampling was 8:00~9:00 and 16:00~17:00. What it monitored was ammonia emission potentials from the soil-water surface after surface application of urea, without taking into account the volatilized ammonia captured by the rice canopy. Consequently, the dynamic chamber technique tended to overestimate ammonia emissions from paddy fields at the booting stage of rice after urea application. In using this technique to monitor ammonia emission in different treatments and their replicates, it is essential to have uniform air chamber specifications and air flow rates. Like the dynamic chamber technique, the static chamber technique monitored ammonia emission from the soil-water surface. However, the former was much higher than the latter in air exchange rate in the chamber, because the air exchange was somewhat hindered in the chamber of the latter. So the ammonia flux monitored with the static chamber technique was much lower than that monitored with the dynamic chamber technique. 【Conclusion】The assessment of ammonia emission from paddy fields after fertilization at the booting stage of rice should be based on what is obtained with the micrometeorological IHF method because it monitors ammonia emission above the canopy of the crop. As when topdressing urea is applied to rice at its booting stage, the crop has already formed its canopy, which covers almost the whole soil-water surface of the paddy field and recaptures and absorbs the ammonia emitted from soil-water surface. Hence as a matter of fact, the ammonia emission in the rice ecosystem is not serious. The dynamic chamber technique is only suitable for monitoring ammonia emissions from soil-water surface when the rice plant is still at its growth stages after transplanting.
Key words:  Ammonia emission  Micrometeorological technique  Dynamic chamber technique  Static chamber technique  Booting stage of rice  Rice canopy