Ammonia Volatilization and Nitrogen Utilization Efficiency in Response to Urea Application in Rice Fields of the Taihu Lake Region,China附视频

<正>Ammonia volatilization losses,nitrogen utilization efficiency,and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town,Changshu City,Jiangsu Province,China.The N fertilizer treatments,applied in triplicate,were 0 （control）,100,200,300,or 350 kg N ha-1.After urea was applied to the surface water,a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field.Total N losses through ammonia volatilization generally increased with the N application rate,and the two higher N application rates (300 and 350 kg N ha-1) showed a higher ratio of N lost through ammonia volatilization to applied N.Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N.Increasing the application rate generally decreased the ratio of N in the seed to N in the plant.For all N treatments,the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%.Surplus N with the highest N rate resulted in lodging of rice plants,a decreased rate of nitrogen fertilizer utilization,and reduced rice yields.Calculated from this experiment,the most economical N fertilizer application rate was 227 kg ha-1 for the type of paddy soil in the Taihu Lake region.However,recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.