Effect Of Type And Application Rate Of Urea On Yield And Nitrogen Utilization Of Maize

The experiments in 2013 showed that the single basal of polypeptide and coated urea is a better fertilization mode to maize yield formation and nitrogen uptake. In 2014, we study further the effect of types and nitrogen application amount on grain yield and nitrogen use efficiency of maize on this basis. We want to provide a theoretical basis and technical guidance for fertilization of maize production in hilly area of central Sichuan.1. Effects of different types of nitrogen fertilizer and amount of nitrogen on yield and benefit. In the late growth stage the dry matter accumulation and distribution of dry matter to grain rate can affect the grain yield of maize, application of nitrogen fertilizer under a single basal and the same amount condition, compared with common urea, polypeptide and sulfur coated urea could significantly increase the dry matter accumulation with maize in anaphase, the amount of dry matter accumulation was increased by 13.95% and 10.07% after silking stage, increased by 7.26% and 5.79% in maturing stage; Among the different treatments with dry matter proportion to the distribution of grain is obvious, the reason for this difference is mainly caused by the amount of nitrogen application. Under a single basal and the same amount condition, the difference of dry matter rate to the distribution of grain was not significant of three kinds of urea, dry matter distribution to grain rate in high nitrogen treatment was significantly lower than low nitrogen treatment on polypeptide urea and sulfur coated urea. Although common urea twice fertilization could increase the dry matter accumulation and distribution to grain rate, and in production can also increase grain yield, in Sichuan hilly area of corn production mainly in artificial fertilizer, labor costs are the main factors restricting the benefit increase. When the nitrogen application amount was 225kg/hm2, compared with a single bassal of polypeptide urea and sulfur coated urea, in common urea twice fertilization the profits was decreased by 28.98% and 5.62% respectively.2. Effects of different types of nitrogen fertilizer and amount of nitrogen fertilizer on the activity of functional leaves of maize. Under the single basal and same application amount condition, compared with the common urea, polypeptide urea and sulfur coated urea has the effect of slow/control release, using the single bassal not only to increase the chlorophyll content of maize in the late, but also effectively relieve decline of leaf nitrate reductase activity with the growth process. Application of polypeptide urea and sulfur coated urea could delay leaf senescence, maintain the activity of maize plant, increase the dry matter accumulation and nitrogen uptake in the mid-late period of maize, lay a good foundation for maize yield formation.3. Effects of different types of nitrogen fertilizer and amount of nitrogen fertilizer on nitrogen use efficiency of maize. Polypeptide and sulfur coated urea not only to promote the absorption of nitrogen from fertilizer, but also raise the utilization of nitrogen. Under the single basal and same application amount condition, compared with normal urea, nitrogen accumulation increased by 19.91% and 4.86%, agronomic efficiency of applied N increased by 30.57% and 41.05%, Nitrogen use efficiency increased by 76.65% and 18.73%. Ordinary urea topdressing effectively alleviates the phenomenon of nitrogen deficiency in the late growth of maize, but compared with a single bassal of polypeptide urea, the nitrogen absorption efficiency was decreased 15.49%. Application of polypeptide urea can reduce the nitrogen translocation amount of vegetative organs in the middle growth period of maize, delaying senescence of maize leaf, increase the synthesis of nitrogen and it to grain rate of contribution after silking stage.4. Study on reasonable nitrogen planning and management mode. The experimental results of two years showed that compared with a single bassal and bassal+topdressing urea, polypeptide urea and sulfur coated urea has the effect of slow/control release, using the single bassal mode can increase the yield and promote the absorption and utilization of nitrogen on maize. Taking into account the grain yield and economic benefits, although sulfur coated urea can reach the effect of simplified fertilization practices to increase yields, due to the high cost of fertilizer, the profit was decreased 22.11% than polypeptide urea under the same amount of nitrogen application condition, in the production should not be single application, consider giving combined with conventional urea application. Take into account the yield and benefit, a single bassal of polypeptide urea is the best selection, the appropriate reduction amount can also avoid the waste of fertilizer. So we think the best fertilization in this area is single bassal polypeptide urea fertilizer 225kg/hm2.