Abstract:【Objective】Azolla has a highly biological nitrogen fixation ability, however, the growth of Azolla is sensitive to ammonium nitrogen in water and is easily affected by water pH. Research suggests that root zone fertilization of fertilizers can effectively reduce the concentration of ammonium nitrogen in floodwater. However, it is unknown whether culturing Azolla under root zone fertilization of fertilizers can stably inhibit ammonia volatilization and increase yield for paddy soils with different pH values. This study aimed to determine the effect of root zone fertilization of fertilizers in combination with Azolla on ammonia volatilization and rice yield in paddy soils with different pH values.【Method】A pot experiment was conducted with three types of paddy soil (acid, neutral, alkaline), two methods of fertilization (broadcasting and root zone fertilization of fertilizers), and two modes of rice cultivation (with or without Azolla). The ammonia volatilization potential and grain yields of rice were determined for these 15 treatments. 【Result】The results showed that: (1) Under the same nitrogen application rate, root zone fertilization of fertilizers treatments only volatilized NH3-N 1.0-1.8 kg·hm-2(calculated by nitrogen), which were 96% lower than surface application of nitrogen fertilizer for the three types of paddy soil, and Azolla-rice co-culture treatments lowered the ammonia volatilization by 17%-50% when compared with those of rice mono-culture treatments; (2) Compared with rice mono-culture treatments, Azolla-rice co-culture treatments produced higher rice yield. Moreover, root zone fertilization of fertilizers combined with Azolla reached the highest rice yield in black soil, increased by 41% compared with the grain yield of black soil surface application without Azolla. 【Conclusion】 In conclusion, root zone fertilization of fertilizers can significantly reduce ammonia volatilization for paddy soils with different initial pHs while root zone fertilization of fertilizers combined with Azolla has greater potential for increasing rice yield.