Abstract:【Objective】 Ammonia volatilization loss is liable to occur after application of chemical nitrogen fertilizer onto paddy fields. Ammonia emitted from the fields brings about adverse effects on the air and water environment, such as smog and eutrophication. So far little has been reported about studies to compare synchronously the uses of different methods to monitor ammonia emission from paddy fields in China, which affects scientific assessment of ammonia emission from paddy fields and recommendation of rational application of nitrogen fertilizer in paddy fields. 【Method】 Ammonia emissions after basal and tillering fertilizer application were monitored simultaneously with three techniques different in monitoring principle, that is, micrometeorological mass-balance integrated horizontal flux (IHF), dynamic chamber technique and static chamber technique, during the rice growing season of 2017 in the Taihu Lake region. The IHF technique had five ammonia samplers fixed at 0.4 m, 0.8 m, 1.2 m, 1.8 m, and 2.8 m high above the floodwater surface along a pole erected in the center of circular plots (20 m in radius). The dynamic chamber technique was designed to have an air exchange rate of 17 times per minute. And the static chamber technique had the sponge in the chamber replaced daily after N fertilizer application. At the same time, NH4+-N concentration and pH in the floodwater on the surface of the paddy field was measured. 【Result】 Results show that dynamics of the daily ammonia emissions monitored with the three methods were quite consistent in feature. Ammonia emission peaked on the 3~4th day after the basal fertilization and the second day after the tillering fertilization. No significant emission was observed one week after the basal or tillering fertilizer application. In the monitoring, regardless of the methods, ammonia emission fluxes were found positively related to concentration of NH4+-N in the floodwater. The horizontal ammonia flux at 0.4 m above the surface water reached 131.0 μg·m-2·s-1the second day after the basal fertilization, and the flux at 0.8 m above the surface water reached 137.9 μg·m-2·s-1 the second day after the tillering fertilization. The horizontal ammonia flux at 2.8 m was 35.3~66.5 μg·m-2·s-1 and 20.2~39.8 μg·m-2·s-1 after the basal and the tillering fertilization respectively. Cumulative ammonia emission relative to micrometeorological technique, dynamic chamber technique and static chamber technique after the basal fertilization was measured to be 34.6 kg·hm-2, 38.2 kg·hm-2 and 12.9 kg·hm-2, accounting for 32.0%, 35.4% and 11.9% of the basal N fertilizer applied, respectively, and that after the tillering fertilization was 26.7 kg·hm-2, 16.8 kg·hm-2 and 11.8 kg·hm-2, accounting for 33.0%, 20.7% and 14.6% of the tillering N fertilizer applied, respectively. The ammonia emissions monitored with the three different methods displayed nice linear relationships between each other. The dynamic chamber method was quite approximate to the IHF method in total ammonia emission after the basal and tillering fertilizations, while the static chamber method underestimated the actual ammonia emission after the basal and tillering fertilizations, down to only 40.4% of that monitored with the IHF method, because the air exchange in the static chamber tended to be hindered. 【Conclusion】 Loss of the basal and tillering N fertilizers through ammonia emission is serious, when a large amount of nitrogen fertilizer is applied into flooded paddy fields at the time air temperature is high and nitrogen adsorption capacity of rice plant is low. The dynamic chamber method can be used to monitor ammonia emission from paddy fields after basal and tillering fertilizations. However, when the dynamic chamber method is used to monitor ammonia emission from soil-water surface after fertilization, the airflow exchange rates should be taken into account. Furthermore, after basal fertilizer is applied, the ridges of the experimental plots should be made capable of conserving water and nutrients to prevent water exchange through the ridge.