Effects Of Nitrogen Fertilizer Rate And Topdressing Stage On Grain Yield And Quality In Wheat And Relevant Physiological Basis

The physiological basis and effects of nitrogen fertilizer rate and topdressing stage on kernel yield and quality of wheat were systemically studied with two selected winter wheat cultivars, Shangnong8355 with medium gluten potential and Jimai20 with strong gluten potential, using enzymological method and biochemical analysis method. Also the effects of interaction of nitrogen fertilizer rate and topdressing stage on kernel yield and quality at high and medium fertility soil level was studied.The experimentation was carried out in the experimental farm of shandong agricultural university from 2003 to 2005. The main results read as follows:1 Effects of nitrogen fertilizer rate on wheat yield and quality and the relevant physiological basis1.1 Effects of nitrogen fertilizer rate on wheat yield and qualityWhen applied nitrogen fertilizer at the rate of 0-240 kg·hm^-2, the spike number per hectare, the kernel number per spike, the weight per 1000 kernels of Shannong 8355 and the spike number per hectare, the weight per 1000 kernels of Jimai20 increased with the increasing of nitrogen supply. Applied more than 240 kg·hm^-2, the yield components tended to decrease. Therefore, the highest yield could be acquired when applying nitrogen at the rate of 240 kg·hm^-2 for these two cultivars tested, and kernel yield would decrease when apply with more nitrogen.At the rate of 0-240 kg·hm^-2, protein content, protein yield, sedimentation volume, wet gluten content, water absorption would increase with the increasing of nitrogen supply. The dough development time, stability time, and breakdown time would be prolonged, which...