Abstract:
In order to improve nitrogen fertilizer utilization efficiency, Zhengdan 958 was used as the material, all the treatment received the same amount of total nitrogen of 250 kg·ha
-1, four nitrogen(N) fertilization treatments were set with application of different N amounts postponed from jointing N to grain filling N. N-fertilizer basally applied 100% at sowing( N1), 30% at jointing stage and 10% at grain filling stage(N2), 20% at jointing stage and 20% at grain filling stage(N3), 10% at jointing stage and 30% at grain filling stage(N4) from 2021 to 2022, the treatment without N application was setup to calculate nitrogen fertilizer efficiency parameters. The results showed that nitrogen fertilizer postponing application could significantly promote grain filling and increased grain dry matter weight, the date grain filling peak occurred advanced, extended the active period of grain filling, increased average grain filling rate and maximum grain filling rate. The nitrogen fertilizer postponing application could maintain high relative chlorophyll content(SPAD), net photosynthetic rate(Pn), and transpiration rate(Tr), compared with traditional N management practices. The nitrogen fertilizer postponing application significantly increased the nitrogen accumulation, nitrogen fertilizer use rate, nitrogen agricultural efficiency and nitrogen partial productivity at mature stage. The nitrogen fertilizer postponing application significantly in creased the grain per ear, 100-grain weight, the average grain yield increased by 16.32%-34.67%, and the average biomass yield by 12.81%-25.89%. The total N input of 250 kg·ha
-1, nitrogen fertilizer postponing application 20% at jointing stage and 20% at grain filling stage(N3) could effectively matching the supply and demand of summer maize to nitrogen in the black soil area of sand ginger in Hena. Therefore, the postponing application ratio should be considered as a effective measure to enhance grain yield and nitrogen use efficiency of summer maize.