Optimization of Fermented Bio-Regulators Applied to Soil and Leaves for Sustainable Okra (Abelmoschus esculentus) Production

The study aims to develop eco-friendly alternatives to conventional fertilization for the sustainable intensification of vegetable production. This research assessed the impact of locally produced fermented amendments and methods of their application on okra, Abelmoschus esculentus. The experiment employed a randomized complete block design with nine treatments comparing four fermented preparations (plant juice, fruit juice, fish amino acids, and eggshells) applied through subsurface or foliar methods against conventional soil test recommendations. Bio-amendments demonstrated superior performance in maintaining soil nutrient status, with fermented amendments maintaining higher soil organic matter (3.32%) than conventional fertilization (3.18%). Foliar application of fermented fruit juice (FFJ) produced the tallest plants (62.32 cm at 90 DAS), while FFJ-subsurface significantly accelerated flowering (30.50 days). Fish amino acid foliar application yielded the highest number of marketable fruits (3.00), while FFJ-foliar treatment achieved the maximum marketable fruit weight (72.50 g). Bio-amended treatments also influenced fruit nutritional composition, with FAA-subsurface and FPJ-foliar treatments resulting in significantly lower fiber content (24.35%) compared to conventional fertilization (24.46%), while maintaining consistent levels of ash (6.37-6.42%), protein (10.38-10.42%), and fats (1.38-1.41%). Results demonstrate that locally sourced fermented bio-amendments can effectively match or exceed conventional fertilization while supporting soil health, particularly when applied through appropriate delivery methods. This research provides practical guidance for sustainable okra production while advancing the understanding of bio-amendment delivery system optimization.