Plant density is one of the most important cultural practices determining grain yield, as well as
other important agronomic attributes of this crop. Stand density affects plant architecture, alters
growth and development, similarly maize productivity depends upon the external supply of nutrients,
therefore application of nitrogen and adequate planting density might be a feasible technology to
improve maize yield and yield components. A field study was conducted to determine the effects of
plant density and nitrogen fertilization on the growth and yield of maize. The experiment was laid
out in a Randomized Complete Block Design with a split-plot arrangement during the Kharif 2022
season. Treatments consisted of three plant populations (60,000, 75,000, and 90,000 plants ha⁻¹)
as the main factor and three nitrogen levels (100, 150, and 200 kg N ha⁻¹) as the subplot factor.
Results demonstrated that nitrogen application significantly influenced all measured parameters.
The highest nitrogen level (200 kg N ha⁻¹) resulted in the greatest biological yield (13,205 kg ha⁻¹),
thousand-grain weight (301.6 g), grain yield (5,057 kg ha⁻¹), and delayed physiological maturity.
In contrast, plant population had a divergent effect: the highest plant density (90,000 plants ha⁻¹)
produced the maximum biological yield (13,455 kg ha⁻¹), while the lowest density (60,000 plants
ha⁻¹) optimized grain yield (5,091 kg ha⁻¹) and harvest index (41%). The interaction between plant
population and nitrogen was not significant for any parameter. It is concluded that for the maize
variety “Jalal” in the agro-climatic conditions of Swabi, a combination of a lower plant population
(60,000 plants ha⁻¹) with a high nitrogen rate (200 kg ha⁻¹) is the most effective strategy for
maximizing grain yield and harvest index.