Effections Of Different Amount Of Tiller N-Fertilizer On Yield Formation Of Rice And Nitrogen Absorption And Utilization

The experiment was carried out during 2001-2002 in the experimental farm of crop cultivation and physiology key laboratory, Yangzhou University, with 5 typical varieties of rice, mid-season Japonica Guanglingxiangjing and Xiangjing 49, and mid-season Indica hybrid Liangyoupeijiu, 25 you 6547 and Shanyou 63. The effect of different amount of tiller N-fertilizer(ATNF) on yield formation of rice and nitrogen absorption and utilization was studied. The main results were as follows:1 . The effect of nitrogen on yield among varieties of rice were different. Under the condition of this experiment, the yield of Japonica increased with the increasing of ATNF, and the yield reached the maximum when the ATNF added to 15kg/mu. The yield of Indica reached the maximum when the ATNF added to l0kg/mu, and it would decline if we went on adding the ATNF.The effect of ATNF on yield structure among varieties were different.The penicle numbers of per mu of Japonica increased with the increasing of ATNF, mid-season Indica hybrid was something of Japonica, but when the ATNF arrived some value, penicle numbers of per mu would decline. Grain numbers perpanicle of Indica increased with the increasing of ATNF, Japonica increased with the increasing of ATNF under some suitable range, exceed some value the Grain numbers perpanicle would stop increasing. The setting percentage of Japonica were higher than Indica,and tri-line hybrid rice were higher than two-line hybrid rice, The effect of ATNF on penicle numbers on Indica were higher than Japonica. The effect of ATNF on 1000-grain weights were not obvious among varieties of rice.2.The accumulation of dry material increased with the increasing of ATNF during jointing and heading stage, furthermore Indica were higher than Japonica. The accumulation of dry material of Japonica increased with the increasing of ATNF during maturing stage, while which of Indica would decline when the ATNF reached 1 5kg/mu. The proportion of the accumulation of dry material in total dry weight of Indica were higher than Japonica during transplanting to jointing and jointing to heading stage, while the value of Japonica were higher than Indica during heading to maturing stage. There was significant linear correlation between the accumulation of dry material and yield during jointing heading and heading to maturing stage, but it appeared significantparabolic curve correlation during heading stage.3. The effect of ATNF on the concent of effective N in soil among varieties of rice were different The concent of effective N in soil increased with the increasing of ATNF before heading stage. At maturing stage the concent of effective N in soil of the two japonica and Shanyou63 were higher than the other two varieties.4. The rate of N-holding of plants increased with the increasing of ATNF,decIined with the prolonging of the spans of growth period.Total amount of N-absorption(ANA) increased with the ATNF increasing , and there were much variances during the jointing and heading stage. But the variation of the proportion in total ANA in jointing stage was more than that of heading stage, the coefficient of variation were 16.44% and 7.56%. ANA of plant in jointing and heading stage showed significant positive linear relationship with yield(P<0.01), but ANA in maturing stage showed a parabolic curve relationship with yield(P<0.01). ANA increased with the increasing of ATNF during jointing to heading stage,but different breeds had their own optimum proportion in total ANA under high yield condition. The content of N-holding in leafs and blade sheaths increased with the increasing of ATNF during maturing stage, but it declined in ears. The rate of nitrogen transformation in straw of Indica was higher than what of Japonica' s. There were few variances of spikelets produce by per ni trogen in breeds during heading stage.Nitrogen productivity and nitrogen apparent productivity declined with the increasing of ATNF, and Japonica declined much more than Indica.Utilization of nitrogen in this season of littl...