The recent maize experiment commenced in the 2022 fall crop season at the District Al-Hussainiya, Kerbala, Iraq. The experiment comprised two factors, with the first factor a combination of different levels of nitrogen (0, 150, and 300 kg N ha-1) with corresponding labels, N0, N1, and N2, respectively, and three levels of potassium (0, 80, and 160 kg K ha-1) symbolized as K0, K1, and K2, respectively. The second factor was a foliar application of organic nutrients (potassium humate) with two concentrations (1 and 2 g L-1). The organic nutrient application occupied the main plots, while the inorganic fertilizer combinations were in the subplots. The experiment used the maize cultivar ‘Sumer,’ planted in clay mixed soil in a randomized complete block design (RCBD) with a split-plot arrangement and three replications. The results showed a significant effect of adding fertilizer combinations of nitrogen and potassium and foliar application of the organic nutrient potassium humate (2 g L-1) individually and in combinations in most growth, yield, and quality-related traits. The combination of inorganic and organic fertilizers also revealed a significant superiority in enhancing the plant height, number of leaves, ear length, grain rows per ear, grains per row, grain yield, and the percent oil and protein in the maize grains. The interaction between the two study factors contributed to reducing the used amount of mineral fertilizer to 50%, as there was no significant difference between the fertilizer combinations of nitrogen and potassium 150 N + 80 K and 300 N + 160 K kg ha-1 in addition with organic nutrient application at the rate of 2 g L-1.
maize (Zea mays L.), fertilizer combination, nitrogen and potassium, organic nutrient, potassium humate, growth and yield traits
A significant improvement in growth, yield, and quality traits of maize resulted from fertilizer combinations of nitrogen and potassium (N1K1 and N2K2) combined with foliar application of organic nutrients (potassium humate) at the rate of 2 g L-1.