Optimizing Micronutrient Management for Improved Growth and Yield of Broccoli Varieties in Coastal Bangladesh

Broccoli (Brassica oleracea var. italica L.) is a nutrient-dense vegetable, widely valued for its health-promoting properties, yet its cultivation in Bangladesh is hindered by nutrient deficiencies and limited adoption of effective fertilization practices. This study was conducted to evaluate the impact of boron (B) and zinc (Zn) application on the growth, yield, and quality of two broccoli varieties— ‘Green Carpet’ and ‘Early You’—in the Gangetic Tidal Floodplain region, where soil deficiencies in these micronutrients are common. A two-factor Randomized Complete Block Design (RCBD) was employed, with treatments consisting of four B and Zn application levels: control (M0), 2 kg B + 4 kg Zn ha⁻¹ (M1), 2.5 kg B + 4.5 kg Zn ha⁻¹ (M2), and 3 kg B + 5 kg Zn ha⁻¹ (M3). Growth parameters, curd characteristics, and yield were measured to determine the optimal nutrient application level and variety for local conditions. The findings revealed that the combination of 2 kg B + 4 kg Zn ha⁻¹ (M1) with the ‘Early You’ variety (V2) produced the most significant improvements in plant height, leaf growth, stem length and diameter, and primary curd size. The combination of ‘Early variety’ and 2 kg B + 4 kg Zn ha⁻¹ treatment significantly reduced days to curd initiation and produced the highest yield per hectare (20.18 tons), outperforming the control treatment (13.01 tons). This combination also resulted in higher dry weight and greater nutritional density of the broccoli curds, emphasizing the critical role of B and Zn in promoting growth, structural robustness, and curd development. Both primary and secondary curd weights were notably enhanced under M1, particularly with ‘Early You’, highlighting the synergistic effect of variety-specific nutrient optimization. These results underscore the potential of tailored boron and zinc applications to address soil nutrient deficiencies and optimize broccoli production under Bangladesh’s unique agroecological conditions. By adopting the recommended M1 micronutrient treatment and prioritizing the ‘Early You’ variety, local farmers can achieve higher yields and improved broccoli quality, contributing to enhanced food security and economic sustainability in the region. This study provides a foundational framework for future research on nutrient management strategies in broccoli and serves as a model for other regions with similar soil nutrient constraints.