The Effects Of Nitrogen Uptake On The Yield Formation For In Late Hybrid Rice With Different Growth Period Duration

Nitrogen absorption characteristics and its effects of late hybrid rice of different growth period duration were researched on different amount of nitrogen and method of nitrogen application. The main results were as follows:(1)The amount of different nitrogen applicd and methods of nitrogen fertilizer application had important effects on yield for late hybrid rice with different growth period duration. Under zero and 105kg.ha-1 nitrogen application, the yield increased with the extension of the rice growth duration. The highest yield of short growth period duration (growth period is 107 days) was obtained when the amount of nitrogen applicd was 150 kg.ha-1 and application ratios of basic-tille was 80 percents; The highest yield of middle growth period duration (growth period are 115 and 124 days) was obtained when the amount of nitrogen applicd was 195 kg.ha-1 and application ratios of basic-tiller was 70 percents; The highest yield of long growth period duration (growth period is132 days) was obtained when the amount of nitrogen applicd was 240 kg.ha-1 and application ratios of basic-tille was 50%; For the yield components, the way to increasing yield mainly by increasing panicles for short growth period duration, the way to increasing yield mainly by increasing panicles and grain number for middle growth period duration, the way to increasing yield mainly by increasing grain number for long growth period duration.(2) Under this experiment condition, the total absorption of nitrogen increased with the increasing of nitrogen uptake amount for late hybrid rice of different growth period duration. When the amount of nitrogen uptake was 195 kg.ha-1, the total absorption of nitrogen showed a increasing tendency when adding the proportion of panicle nitrogen applying. Under the same amount and methodes of nitrogen fertilizer application, the total absorption of nitrogen increased with the extension of growth period, the main period that produced differences is from heading to maturation. Short and middle growth duration had the advantage of nitrogen absorption in early and medium term, the long growth duration were in late stage. The nitrogen utilization increased with the extension of the rice growth duration and the nitrogen utilization dropped with the decline of the amount of nitrogen uptake and application ratios of basic-tiller.(3) There were differences in plant-type of late hybrid rice with different growth period duration.Plant height and top three internode-length increased with the extension of the rice growth duration. The Plant height and top three internode-length increased with the increases of application and application ratios of panicle. The length,width and angle of the third leaf from top increased with amount of nitrogen application. The length,width and angle of the flag leaf and the second leaf form the top increased with application ratios of basic-tiller.(4)Under the condition of undering low nitrogen application, total dry material production of double season late hybrid rice increased with the extension of growth period. The maximum tillers number and effective panicles of different growth period late hybrid rice varieties decreased with the extension of growth period, while the LAI of heading stage increased with the extension of growth period.The maximum tillers number and effective panicles of the same variety showed adding with the increasing of amount of nitrogen applied and application ratios of basic-tiller. The LAI and SPAD of differentiation and heading stages were adding with the increasing of amount of nitrogen applied and ratio of application of panicle-fertilizer.(5)In Jiangxi, a region of double season hybrid rice production, high yield can be obtainded by increasing nitrogen amount and adding the application ratios of basic-tiller for short and middle growth period varieties.The varieties with the growth duration over 130 days plant in this area is not so safty because of low temperature effection in heading period.