Nitrogen Losses From Shoots Of Different Rice Genotypes With Different Nitrogen Use Efficiency

Eight rice genotypes (Liangyoupeijiu, ceyconic, Yangdao6, Shanyou63, Zhenshan97,Minghui63, wuyujing3, lemont) which was chosen from earlier experiment and hasdifferent nitrogen use efficiency was used in the solution-cultured experiment. The ricewas cultivated with two N levels (20mgN L^-1and 80mgN L^-1)in the life.The closechamber method was used to study the amount and types of volatilization from differentrice genotypes under two N levels, the difference between the ammonia volatilizationfrom rice genotypes and the relation between the nitrogen volatilization from rice shootand the nitrogen use efficiency. The purpose is to screen the rice genotypes with lowammonia volatilization, improve the fertilizer-N use efficiency, reduce the loss of nitrogenfertilizers and reduce the pollution caused by nitrogen volatilization. The result showedthat:1. There was NH₃, N₂O and NO₂ could be checked and measured that volatilized fromthe rice shoot. The total amount of ammonia volatilization was much higher than thetotal amount of N₂O and NO₂ volatilization. Ammonia was the main types of riceshoot nitrogen losses and the ammonia volatilization was the main path of rice shootnitrogen losses.2. The amount of ammonia volatilization of different rice genotypes under two N levelsall became higher with the growth process. The amount of ammonia volatilizationwas the highest in the whole growth at matured stage. Except ceysonic the amount ofammonia volatilization of the other 7 rice genotypes under high N level was significanthigher than their amount of ammonia volatilization under low N level.The amount ofammonia volatilization of groupâ… (Liangyoupeijiu, ceyconic, Yangdao6, Shanyou63)was higher than the ammonia volatilization of groupâ…¡(Zhenshan97, Minghui63,wuyujing3, lemont). 3. The amount of N₂O and NO₂ volatilization of different rice genotypes under two Nlevels was the highest at booting stage in the whole growth and then became lowerwith the growth process. At milky stage and matured stage their amount of N₂O andNO₂ volatilization was the lowest in the whole growth. There was significantdifference between the amount of N₂O and NO₂ volatilization of different ricegenotypes under two N levels. The amount of N₂O and NO₂ volatilization of mostrice genotypes under two N levels was higher than their amount of N₂O and NO₂volatilization.4. Significant variance could be observed in the dry matter accumulation, totalnitrogen assimilation and total nitrogen accumulation of different rice genotypes atdifferent growth stage. The dry matter accumulation and total nitrogenaccumulation of groupâ… (Liangyoupeijiu, Yangdao6, Shanyou63) which has highNUE was higher than the dry matter accumulation and total nitrogen accumulationof groupâ…¡(Zhenshan97, Minghui63, wuyujing3, lemont)wich has low NUE.5. There was a significant negative correlation between the amount of ammoniavolatilization and the total nitrogen accumulation of rice shoot, the nitrogen harvestindex of different rice genotypes, the nitrogen grain production efficiency of differentrice genotypes under high N level. There was a significant negative correlationbetween the amount of ammonia volatilization and the nitrogen harvest index ofdifferent rice genotypes, the nitrogen grain production efficiency of different ricegenotypes under low N level. In this experiment there was no significant correlationbetween the amount of N₂O and NO₂ volatilization and the total nitrogenaccumulation of rice shoot, the nitrogen harvest index of different rice genotypes, thenitrogen grain production efficiency of different rice genotypes under high N level.