Effect Of Nitrogen Fertilizer On Yield Of YangDao6 (Conventional Indica) And Analysis Of Reasons

The experiment was conducted during 2000-2001 using conventional indica variety yangdao6 with five treatments including different nitrogen application time and rate and different ratio of the amount of early nitrogen application to that of lately to investigate the influence of nitrogen application on the components of yield, dry matter production and distribution, nitrogen uptake and grain yield. The main results were showed as following:l.The number of panicles per unit area , the spikelets per unit area could be enhanced and the filed spikelets was decreased and the spikelets per panicle, 1000 filled grain weight were affected insignificantly by increasing the amount of N application of tiller. The grain yield, dry matter production from transplant to internode elongation, dry matter production from adequacy panicles to heading, dry matter production during heading to ripening, and biomass were at the most when the amount of N application of tiller were at the level of 13.5g/m2, 22.5 g/m2, 22.5 g/m2,18.0 g/m2,13.5 g/m2,18.0 g/m2 respectively. Economic coefficient decreased with the increasing of the amount of N application of tiller; N application of tiller enlarged leaf area index to promote the dry matter from transplant to adequacy panicles and from adequacy panicles to internode elongation and during internode elongation to heading, and that enhanced the NAR and LAI at the same time which interacted to lead to the increasing of dry matter from heading to ripening.2.The increasing of the amount of N application of promote-flower promoted the number of panicles per unit area and spiklets per unit area, but resulted in the decreasing of filled grain percentage significantly. Grain yield, dry matter production from internode elongation to heading and from heading to ripening, biomass, economic coefficient were at the most at the level of 9-12g/m2, 9.0g/m2 9.0g/m2, 9-12g/m2 and 9.0g/m2 respectively. LAI after internode elongation was enhanced and NAR decreased with the adding of the amount of N application of promote-flower.3. The number of panicles and spiklets per panicle were enhanced and spiklets per unit area was enhanced significantly by increasing the amount of N application of protect-flower, but 1000 filled grain weight decreased significantly. Filled grainpercentage, grain yield, Dry matter production from internode elongation to heading and from heading to ripening, biomass and economic coefficient were all at the most at the level of 9.0 g/m2 N application of promote-flower. The amount of N application of promote-flower affected NAR and LAI significantly at different stage, LAI and NAR(on the average) were at the most at the level of 9.0 g/m2 N application of promote-flower from internode elongation to heading and from heading to ripening.4.To increase the amount of N application made the number of panicles, spiklets per panicle and filled grain percentage decreased; spiklets per unit area had no significant influence on 1000 filled grain weight, grain yield and biomass was at the most at more 15% amount of N application more than standard, economic coefficient was at the most at less 15% amount of N application than standard. LAI increased and NAR decreased with the increasing of the amount of N application.5.The number of panicles and spiklets per unit area were enhanced by increased the ratio of N application of basal and tiller, grain yield was at the most when the ratio is 7 to 3. Dry matter production from transplant to adequacy panicles and from adequacy panicles to internode elongation and from heading to ripening were all at the most at the ratio of 8 to 2, dry matter production was at the most at the ratio of 7 to 3,biomass at the ratio of 8 to 2, economic coefficient at the ratio of 6 to 4,and NAR from transplant to heading and NAR after heading at the ratio of 7 to 3. LAI was all at the most at the ratio of 8 to 2.6.The rate of N application of basal and tiller and heading affected the amount of nitrogen uptake at different times and growing stage significantly,...