AGRONOMIC PERFORMANCE, FRUIT QUALITY ENHANCEMENT AND SOIL HEALTH RESTORATION IN GREEN AND PURPLE OKRA (ABELMOSCHUS ESCULENTUS L.) CULTIVARS UNDER BLACK SOLDIER FLY LARVAL DIGESTATE REGIMES

Abstract

Sustainable nutrient management in intensive vegetable production requires high-value organic alternatives to chemical fertilizers that enhance soil health without sacrificing crop productivity. This study evaluated the comparative efficacy of Black Soldier Fly Larval (Hermetia illucens L., BSFL) digested poultry manure against aerobic poultry manure, farmyard manure (FYM), vermicompost and recommended inorganic fertilizer (RDF) across two phenotypic cultivars of okra (Abelmoschus esculentus L.): 'Parbhani Kranti' (Green, V₁) and 'Kashi Lalima' (Purple, V₂). Executed in a Factorial Randomized Block Design, during 2023-24, the treatment comprising BSFL-digested poultry manure at 7.5 t/acre (T₄) demonstrated statistically superior performance. T₄ recorded maximum plant height (78.34 cm), earliest flowering (43.00 days) and a peak total fruit yield of 13.09 t/ha, significantly outperforming RDF (11.89 t/ha), with the T₄V₁ interaction achieving a maximum yield of 14.41 t/ha. Biochemical profiling revealed that T₄ enhanced total chlorophyll (1.10 mg/100g FW) and anthocyanin content (8.91 mg/100g in T₄V₂), while decreasing crude fiber (9.51% in T₄V₁). Post-harvest soil analysis under T₄ showed reduced bulk density (1.15 g/cm³) and elevated organic carbon (0.53%), along with increased available nitrogen (223.36 kg/ha), phosphorus (64.17 kg/ha), and potassium (382.63 kg/ha). Economically, T₄V₁ yielded the highest benefit-cost ratio (4.30) with net returns of ₹3,48,305/ha, confirming BSFL-digested poultry manure as a viable, highly profitable bio-organic fertilizer for sustainable horticulture.