Effects Of Reduction Application Of Controlled-release Nitrogen Fertilizer On Growth, Nitrogen Uptake-utilization Of Rice And Ammonia Volatilization In Paddy Soil

Field plot experiment was conducted to study on the effects of reduction application of the controlled-released nitrogen fertilizer (CRNF) on plant height,tiller number, photosynthetic characters,yield,N use efficiency (NUE)sammonia volatilization in paddy soil and its dynamic properties in this thesis.The results showed as below:1、The plant height and tiller number of rice were increased with the application increasing of the CRNF,but the percentage of effective panicles was decreased with the increasing of N application when the N application level was beyond a certain level.The tiller number of the Urea treatment was significantly higher than that of the CRNF treatments during the earlier growth stages,but there were no significant differences of tiller number between N application treatments during the later growth stages.The SPAD value of leaf in early rice under Urea treatment was significantly higher than that of the CRNF treatments during the tillering stage,but there were no significant differences of SPAD values between the Urea treatment and CRNF treatments from the tillering stage until the filling stage,there were no significant differences of photosynthetic rate between the Urea treatment and CRNF treatments at filling stage.2、Compared with control treatment,the effective panicles,total grain,yield,output value of double cropping rice were significantly increased and yield of early rice was increased by77.05%to127.12%,the output value was increased by4883.26-8115.21yuan-hm-2;late rice by62.89%to108.05%and5192.15-9010.30yuan-hm"2by supplied nitrogen fertilizer.the effective panicles,rice yield and output value increased with the increasing of CRNF application in early rice,while the effective panicles,total grain,seed setting rate,rice yield and output value were increased with the increase of fertilizer dosage below162kg·hm-2and decreased with the increase of fertilizer dosage above162kg·hm-2.Compared to the common urea,the effective panicles,total grain,yield(increased by4.95%),nitrogen use efficiency(increased by18.01percent point) and agronomic nitrogen use efficiency of early rice were increased,the output value was increased by580.51yuan·hm-2under application of the same nitrogen rate of CRNF;and the effective panicles.total grain,yield,and agronomic NUE were reduced while NUE was increased by18.62to20.17percent point,under application of the reduced nitrogen rate of CRNF;the total grain,yield(increased by9.68%to 27.72%),the output value (increased by1346.72-3818.10yuan·hm-2)NUE(increased by27.95to31.10percent point) and agronomic NUE of late rice were increased,under application of CRNF.Compared with Urea treatment,the net income of early rice was increased by580.51yuan·hm-2under application of the same nitrogen rate of CRNF while reduced under application of the reduced nitrogen rate of CRNF;the net income of late rice were higher under application of CRNF than that of Urea and the net income in the treatment of CRNF reducing nitrogen10%,which increased by3818.10yuan·hm-2.3、Compared with control treatment,the total amount of ammonia volatilization was increased by supplied nitrogen fertilizer,even the common urea treatment and controlled release nitrogen fertilizer were of significant difference in early rice,All other CRNF30%were significantly different in late season.Compared to the common urea,CRNF could reduce the peak of ammonia volatilization and total ammonia volatilization,total ammonia volatilization reduced by42.98%to54.26%in early rice and reduced by27.84%to35.27%in late rice;Comparison between different dosage of CRNF,ammonia volatilization increased with the increasing of CRNF application,but did not reach significant levels.The dynamic characteristics of ammonia volatilization was more quantitatively described as parabola equation than that of Elovich equation.4、Comparison the integral effects of the N fertilizer application treatments on growth, photosynthetic characters, yield, net income of rice and the ammonia volatilization in paddy soil, early rice possess the superior characteristics with the equal in CRNF treatment, but the application amount of the CRNF was reduced by10%was better for the late rice.