Bio-Efficacy and Phytotoxicity of SV SN 40 on Okra (Abelmoschus esculentus L.)

Abstract

A field experiment was conducted to evaluate the bio-efficacy of a novel bio-stimulant, SVSN 40, on growth, physiology, yield and quality attributes of okra (Abelmoschus esculentus L.), along with its phytotoxic safety and post-harvest soil nutrient status. The study was laid out in a randomized complete block design (RCBD) with seven treatments replicated thrice at the C-6 block of Zonal Agricultural and Horticultural Research Station, Navile, Keladi Shivappa Nayaka University of Agricultural and Horticultural Sciences, Shivamogga, Karnataka, during December 2023. Okra variety ‘Arka Nikita’ was subjected to soil drenching of SVSN 40 at 0.5, 1.0 and 2.0 L acre-1 and foliar spray at 1.25, 2.50- and 5.00-ml L-1, applied at 25 and 45 days after sowing (DAS), along with a control. Growth parameters were recorded at 35, 55 and 75 DAS, physiological attributes at 30, 50 and 70 DAS, yield parameters across 26 pickings and phytotoxic effects were assessed at regular intervals after application. Results revealed that SVSN 40 significantly enhanced morphological and physiological traits, with soil drenching at 2.0 L acre-1 registering the maximum leaf area (4217 cm²) and leaf area index (1.171) at 75 DAS, along with higher total chlorophyll content (2.585 mg g-1). Yield attributes were also significantly improved under the same treatment, recording higher fruit weight (10.53 g), number of fruits per plant (54) and yield (12.89 t ha-1) compared to the control (10.45 t ha-1). No phytotoxic symptoms were observed at any dose or method of application. Post-harvest soil analysis indicated efficient nutrient uptake with marginal reductions in available N, P and K. The study concludes that SVSN 40 is a safe and effective bio-stimulant, capable of enhancing okra productivity and physiological performance while supporting sustainable nutrient use, with soil drenching at 2.0 L acre-1 or foliar spray at 5.00 ml L-1 identified as optimal doses.