Effects Of Nitrogen Application Rate On Nitrogen Uptake And Utilization And Nitrogen Metabolism In Longjing 31

As one of the most necessary nutrition elements of rice growth, nitrogen plays an important role in the development process of rice. In the process of production of nitrogen fertilizer,not only large amount of nitrogen losses but also pollute the environment seriously. Under the condition of the field test and micro area test, five kinds of nitrogen application rates,with 15N isotope tracer technique and growth analysis, effects of nitrogen application rate on Longjng 31 dry matter production and distribution, yield and yield components, nitrogen utilization and the influence of nitrogen metabolism were studied, so as to offer reference on the dosage of nitrogen of major rice cultivars in the east of Heilongjiang province. The results showed that:1. From tillering to harvest, the amount of dry matter accumulation of Longjng 31 was gradually increasing, and obtained maximum dry material under the largest fertilizer production; Accumulation of stem and leaf allocation proportion reduced, ear accumulation ratio increased at the same time; Under high nitrogen treatment, Longjng 31 plants dry matter accumulation was too large at the early stage so that it was not conducive to the accumulation of dry matter of grain the mature stage.2. By influencing the rice grain yield components such as spike grain number, effective panicles per unit area and, different amount of nitrogen fertilizer ultimately affected rice yield. Urea in nitrogen fertilizer amount in N3 (application of 180 kg·hm2, similarly hereinafter) processing production peak, continue to increase nitrogen N4 interchange (applied urea quantity is 210 kg·hm-2, similarly hereinafter) compare with N3 processing production in the processing is 2.4%.3.Tillering to jointing stage, plant nitrogen accumulation reaches its peak. It showed that rice at tillering stage and jointing stage need more N supplication. Reproductive growth stage of rice on the N uptake is not high, it is much less than the vegetative growth stage, meeting the needs of the filling stage of rice nitrogen content mainly comes from plant vegetative growth stage absorption of nitrogen transport and redistribution. In the same reproductive stage, the amounts of accumulated nitrogen plant increased with the increasing of nitrogen fertilizer levels.4. Increase the application of nitrogen,isotope 15N in grain allocation proportion droped, the distribution ratio of stem and leaf increased, root system distribution proportion change was not affected by N application rate. It showed that increasing nitrogen application could promote the absorption of the fertilizer nitrogen on vegetative organs. With the increasing of nitrogen level, the rice from the soil to absorb nitrogen accounted for the proportion of the total nitrogen uptake gradually reduced. Fertilizer nitrogen to total nitrogen uptake ratio increase gradually, showed that increasing nitrogen application can reduce the dependence on soil nitrogen rice.5. With the increasing of N application rate, the nitrogen utilization rate of Longjng 31 was reduced, and nitrogen loss was relatively larger. Appropriate nitrogen fertilizer not only increased the nitrogen in the soil residues, but also had the effect of keeping the soil fertility, and reduced nitrogen loss. With the improvement of nitrogen fertilizer input level, the amount of N transshipment between the organs also increased, but nitrogen transshipment efficiency accordingly reduced. High nitrogen treatments on nitrogen transport of grain contribution rate decline significantly.6. With the increasing of N application rate, Longjng 31 harvest organs higher soluble sugar content in first reduced to reduce the change trend of panicle soluble sugar content and no correlation between n application rate. In the early growing stage and even the middle stage of Longjing 31, compared with low nitrogen treatments, N3 treatment on NR, GS, GOGAT were significantly improved, however, further improve the nitrogen fertilizer, the improvement of metabolic enzyme activity effect were not obvious. The reproductive period EP activity declined with the increase of n application rate, high N application rate against birth late rice leaf and the degradation of protein in the plant and transport, and thus play a role in the development of production.