Effect Of The Nitrogen Applied Amount On Growth And Yield Characteristic In Winter Wheat Cultivated Under Water-saving Condition

According to the issue that the growth and development as well as the yield formation mechanism in winter wheat cultivated with water-and N-saving conditions are needed to be further investigated in Hebei plain thus far,a multifactor experiment covering N input levels(i.e.,N240,N180,and N120)and cultivars(i.e.,the control Jimai 22,drought-tolerant cultivar Shimai 22,and high quality cultivar Gaoyou2018)was conducted at Liuijiazhuang experimental station,Hebei Agricultural University during the 2018-2020 growth stages.This study was aimed at understanding of the population growth traits,photosynthetic pigment contents in photosynthesis organ as well as leaf chlorophyll relative steady period(RSP),inorganic nutrient uptake property,seed filling characteristic,and yield traits in the tested wheat cultivars under varied N level treatments together with water-saving irrigation management.The main results are as follows:1.Under normal N supply treatment(N240),the population stem numbers,leaf area index(LAI),and population biomass amounts in the tested wheat cultivars were shown to be follows according to the behaviors:Jimai 22 is the best,followed by Shimai 22,and Gaoyou 2018 is the worst.Under N deprivation treatments(N180 and N120),the above traits are shown to be the best in Shimai 22,followed by Jimai 22,and the worst in Gaoyou 2018.Therefore,the drought-tolerant cultivar Shimai possesses the strong capacity of biomass production at various growth stages under the water-and N-saving cultivation conditions.2.Under normal N(N240)treatment,Jimai 22 plants displayed the highest chlorophyll contents in upper leaves among the tested wheat cultivars,followed by Shimai 22,and the lowest in those of the Gaoyou 2018 plants.Under N deprivation treatments(N180 and N120),according to the behaviors of leaf chlorophyll contents and leaf RSP values,Shimai 22 displayed the highest among the tested wheat cultivars,followed by Jimai 22,and the lowest in Gaoyou 2018.Thus,the enhanced chlorophyll contents and extended RSP of the drought-tolerant cultivar Shimai 22 play an important role in improving the plant dry matter production under the water-and N-saving conditions.In addition,compared with other two wheat cultivars,Shimai 22 also exhibited increased leaf photosynthetic potential under the water-and N-deprived treatments.3.Under normal N treatment,Jimai 22 plants exhibited the best on seed filling rate,followed by those of Shimai 22,and the worst in the Gaoyou 2018 ones.Under N deprivation treatments,according to the values of seed filling rate,the tested wheat cultivars were shown in follow orders:Shimai 22,then Jimai 22,and the end of Gaoyou 2018.The results suggested that Shimai 22 can sustain better seed formation and seed biomass accumulation capacities than other two tested cultivars once treated with low-N level.4.Under normal N supply treatment,the accumulative amounts of nitrogen(N),phosphorus(P),and potassium(K)at spike stage and maturity were shown to be the highest in cultivar Jimai 22,then in Shimai 22,and the lowest in Gaoyou 2018.Under N deprivation treatments,however,the Shimai 22 plants at the late growth stages as mentioned above were shown to be the highest,followed by Jimai 22,and the lowest in those of Gaoyou 2018.The relative more accumulation of the inorganic nutrients,such as N,P,and K contributes greatly to the photosynthetic pigment biosyntheis,extends the leaf RSP,and promotes the population biomass production of the drought-tolerant cultivar Shimai 22 treated with less water and N input levels.5.With the increase of N input level,the yield components,such as population spike amounts,seed numbers per spike,and per-1000 grain weights were shown to be increased in the tested wheat cultivars.Under normal N treatment,according to the behaviors of yield in tested wheat cultivars,Jimai 22 is the best,followed by Shimai 22,and the worst of Gaoyou 2018.Under the N deprivation treatments,Shimai 22 exhibited the best yield behavior,followed by Jimai 22,and the worst of Gaoyou 2018.These results suggested that Shimai 22 can sustain relatively better yield as well as yield components under the water-and N-saving conditions.6.This study indicated that Shimai 22 plants possess improved photosynthetic pigment contents,extended leaf RSP,and enhanced plant growth and development,dry matter production and yield formation capacities under water-and N-saving conditions due to its elevated function in taking up the inorganic nutrients,such as N,P,and K.Under the N deprivation,the high quality cultivar Gaoyou 2018 can sustain relatively better capacities of plants in plant nutrient uptake,photosynthetic biomass and yield production.Our study indicated that Shimai 22 is valuable in cultivation under water-and N-saving conditions in Hebei plain.In addition,the high quality wheat cultivar Gaoyou 2018 is potential in widely cultivation in this ecological region due to its relatively better yield trait behaviors.