Effects Of Nitrogen Fertilizer Rate And Topdressing Stage On Yield And Quality In Wheat

The main objective of this paper is to study the effects of nitrogen fertilizer rate and ratio of base-topdressing on yield and quality of winter wheat. The experiment was conducted at Xuzhou Academy of Agricultural Sciences (XAAS) in 2009-2010, through field observations and laboratory analysis, and the winter wheat variety Xumai 30 was selected as the material. Main result as follows:1,When the nitrogen topdressing conducted in the jointing stage, increasing nitrogen application could improve the wheat population structure, increase effective panicle number and the percentage of productive tillers. The effective panicle number is up to the maximum 369,900 spike/666.7m2 when the nitrogen fertilizer reaches 15kg/666.7m2 and with 5:5 ratio of base-topdressing at jointing stage. Nitrogen topdressing at jointing stage could increase the wheat nitrogen absorption in the middle and later development stage, control the un-effective tilling number, and control the growth development efficiently.2,Application of nitrogen fertilizer contributes to increase the leaf area index. But it shows the same trend during the wheat development between different nitrogen fertilizer treatments. That is increasing at the early development stage, reaching the highest values in the booting stage, and then decreasing at the later stage. Postponing nitrogen can delay the leaf senescence and maintain a high leaf area index. The (5:5) treatment, with a total of 15kg nitrogen fertilizer per 666.7m2 and half of topdressing in jointing stage, reached a maximum leaf area index of 7.84. The leaf area index decreased most slowly in N20 treatment, with a total of 20kg nitrogen fertilizer per 666.7m2, and maintained at a high lever 20 days after flowering stage. Fertilizer can delay leaf senescence, especially in this year when the temperature is suitable for the wheat growth and the wheat growth period is delayed.3,The wheat yield is mainly determined by the composition of panicles, grain number per ear and the grain weight. Grain number per ear and grain weight has closely positive correlation to the yield. In the circumstances of certain panicles, yield shows a rising trend with the increase of grain number per ear and grain weight. All the yields of fertilization treatments were significantly higher than that of control. The grain yield increase with the nitrogen application during the nitrogen application rate of 0-20kg/666.7m1. The grain number per ear reached a maximum number of 37.44 in the (3:7) treatment, which with a total of 15kg nitrogen fertilizer per 666.7m2 and 70% of topdressing in jointing stage. Jointing stage topdressing can improve the grain number per ear.4,Increasing of nitrogen fertilizer and postponing nitrogen topdressing to the jointing stage, could improve the grain protein content, gluten content and sedimentation value. The N20 treatment gave a maximum grain protein content of 14.56%. At the same nitrogen supply level, greater proportion of topdressing gave higher grain protein content. (3:7) treatment had a highest grain protein content of 14.44% in all the treatments with the same total nitrogen application rate of 15kg/667 m2. The nutritional quality and processing quality of wheat could be optimized through the application of nitrogen supply and topdressing stage.