Influence of seaweed extract and humic acid on growth parameters of rabi maize under Southern Odisha conditions

Abstract

Maize (Zea mays) is one of the most important crops among the cereals. It serves as both food and fodder for animals. Being a nutrient-demanding crop, maize requires adequate nutrient supply. However, excessive dependence on chemical fertilisers can negatively affect soil health, creating a need for sustainable nutrient management practices. Seaweed extract derived from the red alga, Kappaphycus alvarezii, rich in phenolic compounds, polysaccharides, and macro-and micro-elements that alter physiological and biochemical processes. Humic acid has biostimulant properties, promotes rapid cell division and helps in the absorption, transportation, mobilisation, and dissolution of metals. Therefore, the present study was undertaken to evaluate the effect of foliar application of seaweed extract from Kappaphycus alvarezii and humic acid, alone and in combination with the recommended dose of fertilisers, on the growth of rabi maize. The experiment was conducted during the rabi season of 2023-2024 at the Post-Graduate Research Farm, M.S. Swaminathan School of Agriculture, Centurion University of Technology and Management, Odisha, using the maize hybrid 'P3396'. The trial was laid out in a randomised block design with three replications and eight treatments. The treatments included a control, RDF (N:P:K @ 120:60:60 kg ha⁻¹), and different concentrations of foliar-applied Kappaphycus alvarezii seaweed extract and humic acid, applied individually and in combination. Growth parameters such as plant height, dry matter accumulation, leaf area, leaf area index, and crop growth rate were recorded. The combined application of RDF with Kappaphycus alvarezii (4 mL L⁻¹) and humic acid (4 mL L⁻¹) significantly improved maize growth, recording the highest plant height (260 cm), dry matter accumulation (1605 g m⁻²), and leaf area (4146 cm² plant⁻¹), representing increases of 25.6%, 32.9%, and 15.9%, respectively, over RDF alone. Therefore, the combined application of RDF with Kappaphycus alvarezii (4 mL/L) and humic acid (4 mL/L) is recommended for Rabi maize cultivation in Southern Odisha.