A field experiment transpired during the autumn of 2022 to study the effects of mineral fertilizer combinations and seaweed extract on maize growth and yield traits in Al-Hussainiya, Kerbala, Iraq. The research had a randomized completely block design (RCBD) arranged in split plots with three replications, where the main plots included seaweed extract (Algazone Mx30) with two concentrations (2 and 4 ml L^-1). The subplots included mineral fertilizer formulations of nitrogen (0, 150, and 300 kg ha^-1) and phosphorus fertilizers (0, 50, and 100 kg ha^-1). The maize cultivar ‘Maha’ was the sample used for the experiment. The results showed excellence in treatments, which represents seaweed extract with a concentration of 4 ml L^-1 combined with 150 N + 50 P giving better performance in plant height (188.82 cm), leaves plant^-1 (15.65), leaf area plant^-1 (5548.3 cm²), rows per ear (16.46), grains row^-1 (39.41), grain yield (10.74 t ha^-1), and protein concentration (13.81%) in grains. With the interaction of two study factors, the mineral fertilizer use had a 50% reduction because there was no significant difference between the two doses of NP, i.e., 150 N + 50 P and 300 N + 100 P kg ha^-1, and the seaweed extract (4 ml L^-1).

Keywords: Maize (Zea mays L.), seaweed extract, fertilizer combination, growth and yield-related traits, quality attributes

Key findings: A significant improvement in growth, yield, and quality traits of maize was evident due to the combined use of nitrogen and phosphorus fertilizers with the foliar application of seaweed extract (4 ml L^-1).