Abstract:

Nitrogen application rate and base-topdressing ratios of nitrogen fertilizer are key factors affecting wheat yield. Different nitrogen application rate and base-topdressing ratios of nitrogen fertilizer have important effects on the number of tillers and yield components at different growth stages of wheat. Exploring the optimal combination of nitrogen application rate and base-topdressing ratios of nitrogen fertilizer can effectively improve wheat yield. A two-factor design was used in this study. Four different nitrogen application rates were set for the main treatment, including F₁ 120 kg/hm², F₂ 180 kg/hm², F₃ 24kg/hm² and F₄ 300 kg/hm². Six different base-topdressing ratios of nitrogen fertilizer were set for secondary treatment, including N₁ 3:7, N₂ 4:6, N₃ 5:5, N₄ 6:4, N₅ 7:3 and N₆ 10:0. Nitrogen topdressing was carried out at the jointing stage. The number of internal tillers was investigated at seedling stage, overwintering stage, jointing stage, booting stage and maturity stage. The 1000-grain weight was measured at the filling stage. Effective spike number, grain number per spike, and 1000-grain weight were measured at the maturity stage. The results showed that the yield of ‘Zhengmai 369’ was significantly affected by nitrogen application rate, base-topdressing ratios of nitrogen fertilizer, and their interaction. Among them, F₃ effectively increased the population number of wheat, F₂ reduced the tiller loss rate at the heading stage, and F₂ had the greatest effect on the yield of ‘Zhengmai 369’, increasing yield by 9.74%-33.58%. Wheat yield decreased with the increase of nitrogen fertilizer proportion in the base fertilizer. Compared with N₁, N₂ and N₃, wheat yield decreased significantly under N₅ and N₆. Under the interaction of nitrogen application rate and base-topdressing ratios of nitrogen fertilizer, F₂N₁ had the highest wheat yield, with a maximum increase of 52.12% compared to other treatments. The results showed that nitrogen application rate and base-topdressing ratios of nitrogen fertilizer affected the yield of ‘Zhengmai 369’ by affecting the effective spike number and 1000-grain weight. Among the treatments, the wheat yield under the interactive treatment of F₂N₁ reached the highest. This study provided an important theoretical basis for optimizing high-yield cultivation measures of ‘Zhengmai 369’.

Key words: wheat, yield, nitrogen application rate, base-topdressing ratios of nitrogen fertilizer, cultivation measures