Effect of humic acid and iron on growth and yield of rabi maize (Zea mays L.)

In the Rabi season of 2024-25, a field experiment was meticulously conducted at the Crop Research Farm, Department of Agronomy, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, on sandy loam soil with a neutral pH. The study aimed to explore the impact of foliar applications combining humic acid and iron, administered at varying dosage levels, to assess their efficacy and influence on growth, yield and economics of the crop Maize. The experiment was designed using a randomized block design (RBD) with ten treatments and three replications. The treatment details are as follows T1. Humic Acid (Control) + Iron 0. 1%, T2. Humic Acid (Control) + Iron 0. 2%, T3. Humic Acid (Control) + Iron 0. 3%, 4. Humic Acid (2 gm/lit.) + Iron 0. 1%, T5. Humic Acid (2 gm/lit.) + Iron 0. 2%, T6. Humic Acid (2 gm/lit.) + Iron 0. 3%, 7. Humic Acid (4 gm/lit.) + Iron 0. 1%, T8. Humic Acid (4 gm/lit.) + Iron 0. 2%, T9. Humic Acid (4 gm/lit.) + Iron 0. 3% and T10: Control (120:60:40) NPK kg/ha.  The results revealed that Treatment 7 (Humic Acid 4 gm/L + Iron 0. 1%) produced the tallest plants, reaching an impressive height of 167. 47 cm. Meanwhile, Treatment 8 (Humic Acid 4 gm/L + Iron 0. 2%) had the highest yields and productivity. It delivered the most cobs per plant (1. 80), the highest number of rows per cob (16), and the heaviest plant dry weight (109. 16 g). It achieved the highest grain yield (6. 52 t/ha) and stover yield (14. 48 t/ha).