Nitrogen use efficiency and ammonia volatilization from rice shoot in late growth stages

A pot experiment was conducted to study the relationship between ammonia volatilization from rice shoots and nitrogen use efficiency. The ammonia volatilization was assessed using close chamber method. The nitrogen use efficiency of four different rice genotypes and two rice genotypes under different nitrogen levels was calculated. The results showed that there were negative relationships between ammonia volatilization and total nitrogen accumulation in rice shoot, seed nitrogen accumulation and nitrogen harvest index. A significant negative relationship was observed between total nitrogen accumulation in rice shoot and ammonia volatilization. There were also relationships between ammonia volatilization and the indices of fertilizer-N use efficiency under four different nitrogen levels, and the amount of ammonia volatilized from rice shoot increased with nitrogen fertilizer application rate. Significant negative relationships were observed between ammonia volatilization and indices of internal nitrogen use efficiency and agronomic nitrogen use efficiency.