The Effects Of The Amount And Time Of Nitrogen Applied On The Quality And Yield Of Rice

The exprimem was carried out in 2000-2001. The effects of the amount and time of nitrogen applied on the quality and yield of rice were studied in either pot or field with shanyou6, wuyujing, wuxiangjing9 and other rice. The main results as follows:(1) When increasing the amount of nitrogen, the milling quality of Japonica and Indica were both improved to some extent, and the milled rice percentage of shanyou63 and wuyujing3 was increased by 5.1% and 7.4%. respectively. Head milled rice of wuxiangjing9 was increased by 6.5% with nitrogen application being postponed.(2) The effect of nitrogen fertilizer on chalkiness varied with varities. When the amount of nitrogen fertilizer was increased, the percentage of chalkiness in shanyou63and wuxiangjing9 were increased by 47% and 13%, respectively, but in wuyujing3 it was decreased by 264%. The percentage of chalkiness with nitrogen applied by 7:3 and 9:1 was respectively, less 14% and 7% than that of nitrogen applied by 5:5.(3) The effect of nitrogen on ge! consistency varied with diffierent experimental conditions, with increasing the total amount of nitrogen in specific range. The gel consistency in shanyou63 and wuyujing3 became soft significantly. When spikelet-promoting fertilizer and spikelet-protecting fertilizer were increased. Gel consistency of wuxiangjing9 became soft significantly, but when the time of fertilizer applied was postponed, it became rigid.(4) No siginificant differences of amylose content in different varities was observed. But there was a significant influence of spikelet-promoting fertilizer on the amylose content in wuxiangjing9 (F=3.98*)and there was a trend of theamylse content which was decreased with the amount of nitrogen fertilizer increased.(5) There was an obvious difference of protein content in different varities. The lower content of protein in wuyujing3 was found, but the difference was small in large amount of nitrogen fertilizer treatments. The significant effects of fertilizer applied in late stage on prolamin and glutelin were observed. There was a trend that the absolute contents of prolamin in yangdao6, guangliangyou6 and T022 were increased with the increased amount of fertilizer applied in late stage, but that of huaidao6 was decreased.(6) There was a conic relationship between pead viscosity and the amount of nitrogen. The taste quality of rice was improved with the increase of nitrogen. When the peak viscosity is at tiptop, the amount of nitrogen in shanyou63 was less than that of wuyujing3. So In terms of the amount of nitrogen which destroried taste quality of rice, the amount of nitrogen in Japanica is larger than that in Indica. The larger breakdown of starch which reflected gel consistency and other indexes was, the better the taste quality was. The effect of nitrogen on breakdown in Indica was much more than that in Japanica.But in the middle and large amount of nitrogen fertilizer, there was a trend that breakdown between Japanica and Indica were increased with increasing nitrogen application.(7) SPAD-502 may be an adptive tool to supervise nitrogen application. There was a positively significant correlation between both of the chlorophy II contents, the nitrogen content and SPAD value, and there was a significantly expotential regression correlation between SPAD value and the protein content in milled rice. It's not advisable to apply spikelet-fertilizer when the SPAD value of shangyou63 and vvuyujing3 were 45.75 and 46.78, respectively. Considered the effects of spikelet-protecting fertilizer on yield and quality of rice, the suitable amount of spikelet-protecting fertilize was 14 kg/'tno carbamide.