Optimising Okra (Abelmoschus esculentus L. Moench.) Fruit Yield and Physiological Responses through the Integration of Foliar Fertiliser at Different Timings

Abstract

Okra is an important vegetable crop with high nutritional and economic value. Various approaches have been attempted to increase its production, including foliar fertilisers. This study aims to determine the optimal time to apply foliar fertiliser in a day to improve the final yield in Abelmoschus esculentus L. var. Torpedo and evaluate okra’s growth and yield responses by integrating foliar fertiliser as supplementary fertiliser with granule fertiliser in a controlled environment. The study was conducted in a rain shelter under a randomised complete block design with 3 blocks comprising 3 replications within each block. The treatments involved a combination of foliar and granule application at different timings: sunrise, midday, and dusk, and solely granule fertiliser at labelled recommended rates. The control group was treated with only granule fertiliser at the same rate as the combined foliar and granule application. The study found that the application of foliar fertiliser during dusk (6–7 p.m.) showed a higher trend of potential yield, which revealed the potential of dusk foliar fertiliser application timing as the optimal timing for foliar fertilisation. The study also demonstrated that incorporating liquid foliar fertiliser with granular fertiliser can enhance nutrient uptake and promote plant growth, leading to a more sustainable farming practice by reducing inorganic soil granule fertilisers. The potential yield under the combined fertiliser treatments was 5% to 20% higher when compared to experiment control while comparable to the conventional fertiliser application treatment, despite using 45% less nitrogen. Therefore, the study suggests that farmers integrate foliar and soil fertilisation methods to achieve optimal crop yield production and promote sustainable farming.