To further improve the N utilization efficiency of oilseed flax,and to reduce the amount of chemical fertilizer input in the northwest arid region,field two-factor split plot experiment was carried out to study the regula-tory effects of 3 N application levels(N1:60 kg·hm-2;N2:120 kg·hm-2;N3:180 kg·hm-2)and 3 application periods(T1:all basal;T2:2/3 basal +1/3 topdressing at the beginning of bud emergence;T3:1/3 basal +1/3 topdressing at the beginning of stem division +1/3 topdressing at the beginning of bud emergence)on N metabolism and N fertiliz-er utilization efficiency of oilseed flax in dryland.Results showed that the activities of N metabolism enzymes,leaf N accumulation and transport and grain yield increased and then decreased with N fertilizer application.At the same time,N agronomy efficiency and partial N productivity decreased.During the fertilization periods,the above indicators were the highest under T2 treatment.The comprehensive operation of N fertilizer showed that under N2T2 treatment,the activities of N metabolizing enzymes(nitrate reductase,nitrite reductase and glutamine synthe-tase)and N accumulation were significantly increased by 14.21-34.93%,18.66-29.27%,14.92-55.82%and 10.63-36.74%compared with the traditional model(N3T1),and were increased dramatically by 22.75-54.84%,23.62-69.81%,43.61-78.09%and 23.33-57.88%compared with no N application(CK).The grain yield,N utiliza-tion efficiency in grain,pre-anthesis N transport and their contribution to grain were higher under N2T2 treatment,which was 14.35%,4.20%,28.45%and 17.37%higher than other treatments on average.The correlation analysis showed a significant positive correlation between N accumulation and N metabolism enzyme activity,N transport,grain yield,and N utilization efficiency.In conclusion,application of 120 kg·hm-2 N fertilizer at the rate of 2/3 bas-al +1/3 topdressing at the beginning of budding stage could significantly improve N metabolism enzyme activities and N fertilizer utilization efficiency of oilseed flax,which might be used as a N fertilizer operation mode to achieve efficient production in dryland.
维普
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