Objective To explore the impact of the rice-red claw crayfish farming model on ammonia volatilization loss in paddy field and nitrogen accumulation in rice plants, and provide a theoretical basis for optimizing input management in paddy field and efficient utilization of resources.

Method Field experiments were conducted with three treatments including blank control (CK, rice monoculture without fertilizer application and crayfish introduction), conventional rice monoculture (RM), and rice-red claw crayfish farming (RN). The monitoring areas of RN treatment included the rice planting area and ditch area. The variation trend of soil ammonia volatilization and nitrogen use efficiency of rice in different rice ecosystems were determinated.

Result The RN mode in the ditch area could effectively reduce the volatilization flux of ammonia volatilization compared to the rice planting area and the RM mode. Under higher nitrogen input conditions, the RN mode did not significantly increase the loss of ammonia volatilization in paddy field, and the loss value showed a decreasing trend. The volatilization flux of ammonia volatilization in paddy field was significantly positively correlated with the surface water ammonium nitrogen (NH₄⁺-N) and total nitrogen (TN) concentrations (P< 0.05). The RN mode increased soil nitrogen content through higher nitrogen input, and the crayfish activity improved soil aeration to promote nitrogen absorption by rice roots, thereby significantly increasing nitrogen accumulation in rice plants (10.2%)(P< 0.05).

Conclusion Compared to the RM system, the RN system has a higher nitrogen assimilation potential, which could potentially inhibit soil ammonia volatilization, increase nitrogen absorption of rice and accumulation, and achieve higher nitrogen use efficiency.