Effect of spraying with equilibrium biostimulant compound, spraying stages and plant density on some growth and biochemical traits of maize plant

This study evaluated the effects of plant density, a biostimulant (Equilibrium: a blend of amino acids and seaweed extract), and different spraying stages on maize growth and nutrient uptake using a split-split plot design with three replications. Conducted in Karbala Province during the 2023 autumn season, the experiment tested three Equilibrium levels (0, 2, and 4 L·ha⁻¹), three spraying regimes (5–6 leaf stage; 5–6 leaf + tasseling; and 5–6 leaf + tasseling + grain filling), and three plant densities (38,095; 53,333; and 88,888 plants·ha⁻¹). The 2 L·ha⁻¹ level significantly improved traits like leaf area (4971 cm²), leaf area index (2.89), and nutrient absorption (N, P, and K) without differing from the higher 4 L·ha⁻¹ rate. Spraying at two stages enhanced potassium absorption and oil content (4.32%) and was as effective as three-stage spraying. Higher density (88,888 plants·ha⁻¹) yielded superior vegetative traits and nitrogen uptake, while the medium density (53,333 plants·ha⁻¹) maximized phosphorus and potassium absorption. Most interactions among treatments were not statistically significant, except specific combinations (e.g., 2 L·ha⁻¹ + 53333 plants·ha⁻¹) that enhanced P and K uptake. Overall, the 2 L·ha⁻¹ application combined with optimal density and timing provided effective maize performance enhancement.