Effects Of Different Nitrogen Management On The Yield For Mation And Nitrogen Absorption And Utilization Of The Subspecific Hybrid Medium Rice Yongyou 4949

This paper takes the rice paddy field which was planting barley before in northern part of Hubei Province as the research object and Yongyou 4949 as materials to carry out this experiment. We took the nitrogen input amount which can get high yield as HY, then setting up five different nitrogen fertilizer levels(HY, HY ± 15%, HY ± 30%), and when the total amount of nitrogen is HY, the base tillering fertilizer: panicle fertilizer is 10:0,7:3,6:4,4:6,3:7, five different distribution ratio of nitrogen, and setting the N0 treatment separately, to evaluate the Effects of different nitrogen fertilizer and different distribution ratio of nitrogen fertilizer on yield formation in rice and its Nitrogen use efficiency. The purpose is to find the best application amount and the best distribution ratio of nitrogen and provide a theoretical basis for the rational application of nitrogen fertilizer. The main conclusions are as follows:1. We found that the nitrogen fertilizer was about 270 kg ? hm-2 is the best N application amount. In this nitrogen inputs amount, the yield of Yongyou 4949 can reach about 13.77 t ? hm-2 which has no significant difference with the yield of 14.60 t ? hm-2 whose nitrogen inputs amount was 351 kg ? hm-2. The best distribution ratio of nitrogen is from 6:4 to 4:6. Either the proportion of base-tiller fertilizer or panicle fertilizer is overtop, it is not good for graining a high yield.2. If the nitrogen fertilizer increased, the Effectsive panicles increased as well, while the 1000-grain weight and seed setting rate turn down. To the variety of Yongyou 4949, the seed setting rate and 1000-grain weight in HY treatment was decreased by 3.4% and 0. 5% than N0 treatment, while the Effectsive panicles in HY treatment was increased by 66.17% than N0 treatment, the yield was increased by 62.76% finally.A reasonable distribution ratio of nitrogen is conducive to coordinate the relationship between Effectsive panicles and panicle number and seed setting rate and 1000-grain weight, and then the yield is high finally. This study shows that, when therefore the final yield is higher as well. This study shows that, when the base-tiller fertilizer: panicle fertilizer is from 6: 4 to 4: 6, it can have appropriate panicles, and obtain higher panicle number, the final yield is higher as well. If the base-tiller fertilizer is higher, it has more Effectsive panicles, but the panicle number is lower; if the panicle fertilizer is higher, the panicle number increased, but the Effectsive panicles decreased.3. Applicating nitrogen fertilizer rationally can improve the population quality of rice Effectsively. Nitrogen fertilizer inputs increased the LAI of rice groups and the photosynthetic potential from full-heading stage to maturity stage of rice significantly. The more nitrogen fertilizer, the greater the amount of dry matter accumulation after flowering and the higher contribution rate to yield. The relationship between LAI in full-heading stage and yield was significant positive correlation, and the correlation coefficient reached 0.801**. The dry matter accumulation from jointing stage to full-heading stage and full-heading stage to maturity stage was also significantly positive correlated with the yield, the correlation coefficient was 0.835** and 0.616** respectively. The most suitable range of LAI is from 7.18~8.09.4. Nitrogen fertilizer inputs influenced the nitrogen content of rice plant and nitrogen fertilizer use efficiency. With the increasing of nitrogen fertilizer, the total nitrogen content of rice plant increased, while the proportion of nitrogen content in grain was decreased. With the increasing of nitrogen amount, the agronomic use efficiency, nitrogen use efficiency in physiology, N partial productivity and nitrogen harvest index of rice were decreased; the nitrogen recovery efficiency of rice increased in the first and then decreased. In this studies, when Yongyou 4949 is in HY treatment(the amount of nitrogen fertilizer was 270 kg·hm-2), the nitrogen recovery efficiency is the highest.With the increase in the proportion of panicle fertilizer, total nitrogen content of rice plant increased. Panicle fertilizer application significantly increased the nitrogen amount of ear and the proportion of the total nitrogen content in the plant. With the increase in the proportion of panicle, the agronomic use efficiency, N partial productivity of rice increased first and then declined, and the HY3 treatment(the base–tiller fertilizer: panicle fertilizer was 6:4) is the highest. The nitrogen recovery efficiency and N harvest index increased as the panicle fertilizer proportionate increased. The NRE and NHI in the HY6 treatment increased by 25.3% and 10.7% respectively than in the HY1 treatment(P <0.05). N physiological use efficiency was declined as the panicle fertilizer proportionate increasing.The studies show that: for planting the Hybrid rice Yongyou 4949 in Hubei Province, choosing the amount of nitrogen at 270 kg·hm-2~290 kg·hm-2 is the best nitrogen application amount. When the base–tiller fertilizer: panicle fertilizer is from 6:4 to 4:6, the population quality is good, the gain yield and nitrogen use efficiency is higher too. Therefore, it is the preferred fertilization program.