Effect of the Rate of Nitrogen Application on Dry Matter Accumulation and Yield Formation of Densely Planted Maize

Abstract

Planting maize (Zea mays L.) reasonably densely and adding amounts of appropriate nitrogen fertilizer are essential measures to improve the efficiency of maize yield and nitrogen use. In this study, two planting densities of 7.5 × 104 plants ha−1 and 12.0 × 104 plants ha−1 were established with the maize varieties DengHai 618 (DH618) and XianYu 335 (XY335). Simultaneously, 18 levels of nitrogen application were established, including a lack of nitrogen (N0) and increments of 45 kg ha−1 nitrogen up to 765 (N765) kg ha−1. The variables studied included the effects of the rate of nitrogen application on the characteristics of dry matter accumulation and the yield under drip irrigation, and they were integrated into water–fertilizer integration. The results indicated that the yield, harvest index, and dry matter accumulation of maize displayed a trend of increasing and then tending to be flat as the amount of nitrogen applied increased. The use of linear plus platform equation fitting indicated that the change in yield with nitrogen administered had the lowest turning point at N = 279 and N = 319, respectively. The next parameter that was measured was the harvest index. When highly dense maize was grown before silking, the rate of nitrogen applied was more obviously impacted by the accumulation of dry matter. The harvest index contributed 22.9–27.2% of the yield, and the total dry matter accumulation before and after silking contributed more than 70% of the production. Increasing the amount of nitrogen fertilizer is beneficial to prolonging the dry matter accumulation time and increasing the dry matter accumulation rate. The accumulation amount of dry matter was positively correlated with accumulation time and rate, and the correlation between dry matter and accumulation rate was greater. In conclusion, applying the right amount of nitrogen can dramatically increase the harvest index, accumulation of materials, and yield, with dry matter accumulation having the greatest influence on yield. The creation of dry matter is influenced by the time and rate of its accumulation, with its rate serving as the primary controlling factor.