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The Hefei Research Institute has found that the application of slow-release urea in combination with deep water irrigation can reduce ammonia volatilization in paddy fields. Author/Source: Chinese Academy of Sciences; Date: 10-16-2019; Clicks: 12. Recently, researchers led by Yang Yang from the Institute of Technical Biology and Agricultural Engineering at the Hefei Institute of Physical Science, Chinese Academy of Sciences, have made progress in studying the coupled response mechanisms of water and fertilizer on ammonia volatilization in paddy fields. This work provides a theoretical basis for the research, development, and application of new environmentally friendly and efficient fertilizers. The relevant findings were published in the international journal Journal of Cleaner Production. Ammonia volatilization from paddy fields is an important factor affecting the efficient use of fertilizers in rice cultivation. However, the synergistic effects of irrigation and slow-release fertilizers on ammonia volatilization in paddy fields have not been studied, and there is still no consensus regarding the contribution of field factors to ammonia volatilization and the role of the rice canopy in ammonia volatilization in farmland. By applying different irrigation and fertilization treatments, the research team used the ammonia sensor method explored earlier to conduct rapid and highly sensitive measurements of ammonia volatilization from paddy fields as well as ammonia flux within the rice canopy, in order to determine the optimal combination of water and fertilizer treatments for reducing ammonia volatilization in paddy fields ； At the same time, the variation mechanisms of ammonia volatilization in paddy fields are systematically revealed based on data from various field factors. The study results show that the application of nitrogen fertilizer significantly increases ammonia volatilization in paddy fields. The application of slow-release urea combined with deep water irrigation is the best water and fertilizer treatment combination for reducing ammonia volatilization in paddy fields. Ammonia volatilization in paddy fields is closely related to surface water pH, ammonium nitrogen concentration, and gamma value. The main reason why deep irrigation and slow-release urea can reduce ammonia volatilization in paddy fields is that they significantly lower the aforementioned surface water parameters. Based on the role of the rice canopy in ammonia volatilization in farmland, the growth period of rice can be roughly divided into 4 stages. Considering the entire growth period, the rice canopy acts as a sink for ammonia in field ammonia volatilization. The ammonia flux in the rice canopy is relatively low, so it has a weak impact on the total amount of ammonia volatilized in the field; however, it shows a strong negative correlation with rice grain yield, and can be used as an alternative parameter for evaluating the potential of rice production. Comprehensive analysis suggests that the application of slow-release urea in combination with deep water irrigation can reduce ammonia volatilization in paddy fields, and increase rice grain yield, water productivity, and nitrogen fertilizer utilization; therefore, it holds promise for use in efficient rice production. These research findings can provide scientific guidance for the promotion of environmentally friendly new fertilizers and for the management of water and fertilizer in rice cultivation. This work was supported by the **National Natural Science Foundation**, key research and development programs, the Chinese Academy of Sciences’ Science and Technology Service Network Program, and major science and technology projects in Anhui Province.