Nitrogen Loss In Winter Wheat High Yield And Quality Nitrogen Fertilizer Management Model

The formation of winter wheat yield and quality is closely related to nitrogen?N?nutrition,appropriate application of N fertilizer can increase winter wheat yield and improve wheat quality.However,excessive levels of N input can cause a series of environmental problems.Therefore,how to rationally adjust the N fertilizer operation mode so as to minimize the negative impact on the environment while improving production and improving quality has become an urgent problem in winter wheat production.In this study,we conducted the same program simultaneous N fertilizer operation experiment in Hebei Zhengding and Hebei Qingyuan in 2016-2018 to study the environmental effects of N fertilizer operation model in high-yield and high-yield production of winter wheat,in order to construct a N fertilizer operation mode that coordinates agricultural,economic and environmental optimization.The test materials were medium-gluten wheat Heng 4399,medium-gluten wheat Jimai 22 and strong-gluten wheat Gaoyou 2018.The main test results are as follows:?1?The yield of winter wheat in Zhengding two seasons was the highest under N₂₂₅treatment,and the yield of winter wheat in Qingyuan was the highest under N₁₈₀ treatment,in a certain range of winter wheat,appropriate N application can significantly increase winter wheat yield,and the yield of winter wheat decreases with the increase of N application rate,but the quality was significantly improved,the quality indicators such as the developement time and stability time of Zhengding 2016-2017 winter wheat?Heng4399?and 2017-2018 winter wheat?Gaoyou 2018?were higher under N225 and N293treatments,respectively,the quality indicators such as the developement time and stability time of Qingyuan 2016-2017 and 2017-2018 winter wheat?Jimai 22?were higher under N₂₅₅ and N₃₃₀ treatments.The N surplus of each treatment increased with the increase of N application rate,Zhengding 2016-2017 season winter wheat only N₀ treatment showed N deficiency,the treatment of winter wheat N0,N158 and N225 in 2017-2018 showed N deficiency,the N0 and N100 treatments of the winter wheat in Qingyuan 2016-2017 showed a N deficiency,while the winter wheat in the 2017-2018 season only treated with N₀ as a N deficiency,the N surplus of winter wheat when it reached high quality exceeded the international farmland N surplus standard.Considering the yield and quality of winter wheat,the threshold of positive N input was 260.0-300.0 N/ha,and the current threshold of Qingyuan N input should be higher than 223.5 kg N/ha,but the environmental risk was too high,considering the environmental benefits of winter wheat,the positive N input thresholds were 149.9-255.6 and 237.9-260.0 kg N/ha,respectively,and the Qingyuan nitrogen input threshold was 204.6-223.5 kg N/ha.?2?With the delay of N-picking period,the yield of topdressing at jointing+booting stage was the highest,which were 1.6%,6.4%,and 18.0%higher than that of jointing,jointing+heading,jointing+flowering,but the difference did not reach significant level.the quality index of formation time and stability time reached the highest at the jointing and booting stage,and the total N emission of the topdressing at the jointing+booting stage was the lowest.Comprehensive yield,quality and environmental benefits,can be used in jointing+booting stage topdressing.Different forms of N fertilizer had no significant effect on wheat yield,but reached the maximum value of 54.5 kg N/ha under the application of urea,compared with the application of ammonium sulfate and ammonium ammonium nitrate,the yield increased by 16.5%and 2.5%,respectively.The stabilization time and formation time were higher than those of ammonium sulfate and ammonium nitrate.However,the total N emission intensity of winter wheat under the urea treatment was the highest,with an increase of 12.4%and 21.2%,respectively.Therefore,considering environmental benefits,the use of urea as a N fertilizer should be reduced in wheat production.?3?There was no significant difference in yield and grain protein content under different recommended topdressing methods,but the yield of recommended fertilization was the highest in strong gluten wheat drones,the increase was 1.4%-31.4%;the highest protein content was observed by farmers,followed by drone recommended by drones;and the minimum total N emission of the drone recommended topdressing mode.Therefore,drone recommendations could be used to diagnose the N status of winter wheat at jointing stage.?4?The correlation coefficient of leaf N content in winter wheat at the flowering stage was higher?R²=0.68?,but the correlation between flag leaf N?inverted leaf?and grain protein content was higher than that of whole leaf N content?R²=0.71?,Significantly;there was a significant positive correlation between leaf SPAD value and leaf N content in different periods of wheat,and R² reached the highest at flowering stage.Therefore,flag leaf SPAD was the best indicator for grain protein content during flowering,which could be used for rapid prediction of grain protein content.In summary,the N input threshold proposed after adding wheat quality to the evaluation index was generally high,resulting in an increase in environmental pollution risk.Therefore,in the production of wheat,calcium ammonium nitrate could be applied through jointing+booting stage.At the same time,the protein content of wheat grain was estimated by using SPAD in flowering stage.A recommended model for N fertilizer staging of winter wheat under high quality conditions was established to guide the application of panicle fertilizer,under the premise of ensuring high quality,we pursue high production,achieve high quality and special use,and reduce environmental N emissions.