Effects Of Fertilization Modes On Population Structure,Nitrogen Metabolism,Yield And Quality Of Winter Wheat

In order to select a fertilizer mode that could meet the requirements of simplified cultivation and stable yield of winter wheat in eastern Hebei province,the winter wheat’Lun xuan 103’was used as the test material.The tested fertilizers included compound fertilizer（CF,N-P₂O₅-K₂O=15-15-15）,quick-release urea（U,N=46%）,slow-release urea（SRU,N=44%）,field and pot experiments was conducted in 2020-2021 and 2021-2022,respectively.The total nitrogen application of 225 kg/hm² was divided into two treatments:50%CF+50%U at jointing stage（conventional fertilizer,T1）,50%CF+50%SRU based application（T2）.The total nitrogen application rate of 180 kg/hm² was set up for 5 treatments:60%CF+40%U at rising stage（T3）,60%CF+40%SRU at rising stage（T4）,60%CF+40%U at jointing stage（T5）,60%CF+40%SRU at jointing stage（T6）,60%CF+40%SRU based application（T7）.The effects of fertilization modes on population structure,flag leaf nitrogen metabolism enzyme activity,photosynthetic characteristics,accumulation,transport and distribution of dry matter and nitrogen,phosphorus and potassium nutrients,root activity,grain yield and quality of winter wheat was studied in order to provide theoretical basis for high-yield cultivation of winter wheat in eastern Hebei province.The main test results was as follows:T2 and T5 treatment was beneficial to maintain a good population structure.With the advancement of growth process,the plant height,main stem leaf age（except regreening stage）and dry matter accumulation of wheat increased,and the total stem number（except booting stage）,leaf area index（LAI,except jointing stage）and total canopy light interception rate（Ca R）increased first and then decreased.At the flowering stage,the above indexes of T2 treatment was not significantly different from those of T1 treatment,but main stem leaf age better than of T3,T4,T6 and T7treatments under nitrogen reduction.There was no significant difference in plant height,main stem leaf age,dry matter accumulation,total stem number,LAI and total Ca R between T5 treatment and T1 treatment,and significantly increased by6.28%,11.61%,10.72%,26.05%,10.54%and 13.16%compared with T7 treatment under the same nitrogen application rate.T2 and T5 treatments could maintain flag leaf physiological metabolism and delay leaf and root senescence.The soluble sugar（SS,except booting stage）,soluble protein（SP）content,glutamine synthetase（GS）,glutamate synthase（GOGAT）,glutamate dehydrogenase（GDH）,nitrate reductase（NR）activity,SPAD value,photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr）and root activity（except 20 d after anthesis）of flag leaves in T2 treatment was not significantly different from those in T1 treatment at different sampling stages,and the nitrogen metabolism enzyme activity and photosynthetic capacity was higher than those in T3,T4,T6 and T7 treatments.The activities of GS,GOGAT,GDH,NR and Pn in T5 treatment was significantly increased by 24.81%,39.99%,56.89%,43.77%and 12.64%compared with T7 treatment.There was no significant differences in nutrient accumulation,grain hardness,grain protein content,nitrogen partial factor productivity（NPFP）,nitrogen harvest index（NHI）and yield between T2 treatment and T1 treatment at maturity stage,and the SS content of grain in field experiment was significantly increased by 17.25%compared with T1 treatment.The nitrogen accumulation at booting stage of T5treatment was significantly increased by 21.42%,28.20%,36.57%and 57.40%,respectively,compared with T3,T4,T6 and T7 treatments under the same nitrogen application rate.The nitrogen distribution ratio of stem and sheath,nitrogen transport amount and transport rate of root,contribution rate of leaf and root nitrogen accumulation to grain,grain number per spike,1000-grain weight of pot,field yield and NPFP was significantly higher than other treatments,and the yield and protein content was not significantly different from T1 treatment.Correlation analysis showed that LAI,SPAD value,Pn,Gs,Tr,root activity at flowering stage was significantly positively correlated with yield and yield components.The activities of GS,GOGAT,GDH and NR in flag leaves at anthesis and 10 d after anthesis was significantly positively correlated with yield.It can be seen that the higher nitrogen metabolism enzyme activity and population photosynthetic capacity of T2 treatment and T5 treatment was the key to yield formation.In conclusion,there was no significant difference between T2 and T5 treatments in population growth indexes,nitrogen metabolic enzyme activities and yield compared with conventional fertilization T1 treatment,and they was higher than other treatments.Therefore,it was recommended to apply 50%CF+50%SRU mixed base under the total nitrogen application rate of 225 kg/hm² in Eastern Hebei Province.Under the total nitrogen application rate of 180 kg/hm²,60%CF+40%U was applied topdressing at jointing stage.