Effects of Foliar-applied Biostimulants and Micronutrients on Growth, Yield and Economics of Winter Maize (Zea mays L.)
A two-year field investigation was conducted during the rabi (winter) seasons of 2024-25 and 2025-26 at the Instructional Farm of the Department of Agronomy, ITM University, Gwalior, Madhya Pradesh, India, to evaluate the effect of foliar-applied biostimulants (chitosan, seaweed extract and protein hydrolysate) and micronutrients (Fe, Zn and I), alone and in combination, on the growth, yield and economics of winter maize (Zea mays L.). The experiment comprised sixteen treatments, namely an absolute control (T1), three individual biostimulants (T2-T4), three individual micronutrients (T5-T7), four dual and triple biostimulant combinations (T8-T11), three dual and triple micronutrient combinations (T12- T15) and a six-component consortium (T16) combining all biostimulants and micronutrients, laid out in a randomised block design with three replications. Foliar application of the consortium treatment (T16) consistently and significantly outperformed all other treatments, recording the tallest plants (224.8 cm), highest dry matter accumulation (273.5 g plant-1), highest SPAD-based chlorophyll content (57.4), heaviest cob with husk (243.8 g plant-1), maximum number of grains cob-1 (685.3), maximum cobs plant-1 (1.88) and the highest grain yield (6.5 t ha-1), representing increases of 21.2, 15.5, 45.0, 46.0, 78.0 and 49.2 per cent, respectively, over the control, pooled across both years. Grain yield showed a strong positive correlation with dry matter accumulation (r = 0.991), stover yield (r = 0.986), cob weight with husk (r = 0.961) and fresh weight (r = 0.969). Grain yield showed a strong linear association with dry matter accumulation (R² = 0.983) among the pooled treatment means, while a multiple regression model incorporating dry matter accumulation, chlorophyll content and cob weight explained 98.8 per cent of the variability in grain yield. Although the consortium treatment produced the highest gross and net returns (₹1,68,496-1,84,664 and ₹1,21,455-1,36,936 ha-1, respectively), the combined micronutrient treatment Fe + Zn + I (T15) recorded the highest benefit-cost ratio (2.83-3.14), indicating greater input-use efficiency. Overall, integrated foliar application of biostimulants and micronutrients improved growth, yield and economic returns of winter maize under the conditions of the two-year field experiment.