Mechanism Of Different Rice Varieties Response To Nitrogen And Effect Of Reducing Ammonia Emission

In order to study nitrogen responsing characteristics and effects of reducing paddyammonia （NH₃）volatilization of high nitrogen use efficiency （NUE） rice at Taihu Lake region, afield experiment was conducted in Wuxi city, which is located in Taihu Lake region. The ricevarieties Zhendao11（Z11）、Wuyunjing23（W23） and Wuyujing3（W3） were choosed asexperimental materials. The research observed the biomass accumulation、 characteristics ofbiological、NUE and NH₃in paddy field with different NUE rice under three fertilizer nitrogenapplication rates（0、200、270kg N/hm2）. In addition, biomass accumulation、nitrogen response androot morphological characteristics of different rice cultivars were observed at three nitrogen levelswith0.2、2、20mmol/L by hydroponic experiment at laboratory. The main results as follows:Under three fertilizer nitrogen application rates, the biomass accumulation of high-NUE Z11、W23are more larger than W3. Under recommended fertilizer nitrogen application rate, the yield ofrice varieties W3、W23、Z11were8.93、8.87and7.41t/hm2respectively; Under high condition ofnitrogen fertilizer application rate, the yield of rice varieties W3、W23、Z11were7.43、9.28and8.98t/hm2respectively.Nitrogen-accumulation ability of high-NUE rice W23、Z11were stroger than low-NUE riceW3at the whole growth stage, but the advantage was mainly embodied after full heading stage ofrice. High-NUE rice W23、Z11had obviously greater nitrogen uptake efficiency （NupE） thanW3and could be defined as highly NupE-based high-NUE rice cultivars.High-NUE rice W23、Z11could take somewhat effect on controlling NH₃volatilization loss inpaddy field under recommened fertilizer nitrogen application rate. When calculating production unitgrain yield of NH₃volatilization in paddy field, high-NUE W23、Z11could play a more effective roleof reducing and controlling NH₃volatilization in paddy field.Hydroponic experiment found nitrogen accumulation、biomass accumulation、root length、rootsurface area and root volume of feed rice were more greater than japonica rice varieties under threenitrogen levels. Feed rice showed stronger ability of absorbing nitrogen during seeding stage,howerve, there was no obvious advantage of NUE between different rice cultivars.