Optimizing Fertigation Levels for Enhanced Growth, Yield, Earliness and Soil Nutrient Dynamics in Okra [Abelmoschus esculentus (L.) Moench] cv. Arka Nikita

Abstract

Okra [Abelmoschus esculentus (L.) Moench] is an economically important vegetable crop, but conventional flood irrigation with blanket fertilizer application restricts nutrient-use efficiency to 40-60%. Such practices also accelerate nutrient leaching, soil degradation and environmental pollution. Fertigation with water-soluble fertilizers (WSF) can improve efficiency by matching nutrient supply to crop demand, yet region-specific dosage recommendations and their effects on soil nutrient dynamics remain poorly documented. This study evaluated fertigation levels for growth, earliness, yield and soil nutrient dynamics in okra cv. Arka Nikita. Field experiments were conducted during late kharif 2025 and summer 2026 at the University of Horticultural Sciences, Bagalkot, Karnataka, on moderately alkaline soil with low available nitrogen, high phosphorus and medium potassium, in a randomized complete block design with nine treatments and three replications. Treatments comprised conventional soil application at 100% of the recommended dose (RDF; 125:75:63 kg NPK/ha), WSF fertigation at 60, 80, 100 and 120% RDF, conventional-source fertigation treatments, farmers' practice and an absolute control. Soil pH, electrical conductivity (EC), organic carbon and available N, P2O5 and K2O were determined before planting and after harvest using standard methods, and changes from baseline were calculated. Growth, earliness and yield data were pooled across seasons and analysed statistically. Fertigation with WSF at 120% RDF (T5) produced the tallest plants (203.44 cm) and heaviest fruits (10.68 g). Fertigation at 100% RDF (T4) recorded the earliest 50% flowering (34.42 days), earliest fruit initiation (37.42 days) and most fruits per plant (43.55) with a 20% lower dose than T5. The absolute control showed the poorest performance across the measured parameters. Post-harvest soil N, P and K declined under T4 and T5 relative to pre-planting levels (N by 2.4–8.9%, P by 10.3–15.6%, K by 1.5–4.6%), reflecting crop uptake, while pH, EC and organic carbon were unaffected. Fertigation with WSF at 100% RDF is recommended for okra under semi-arid conditions, combining earliness, yield and resource efficiency without impairing soil fertility.