Water productivity and yield sustainability of okra (Abelmoschus esculentus L.) under furrow irrigation strategies and nitrogen management in Iraq

In arid and semi-arid regions, furrow irrigation is a common method for okra cultivation, but water losses reduce its efficiency. Alternate furrow irrigation has been shown to conserve water without yield reduction, while nitrogen fertilization plays a key role in enhancing vegetative growth and productivity. Since okra yields in Iraq remain low due to poor irrigation scheduling and imbalanced fertilizer use, optimizing water and nitrogen management is crucial for sustainable production. Therefore, a field experiment was conducted in Abi Ghraq sub-district, Babylon Province, Iraq, during the 2024 growing season to evaluate the effects of furrow irrigation methods (conventional, fixed, and alternate) and nitrogen fertilizer levels (160, 240, and 480 kg N/ha) on okra yield and water productivity. The study was carried out on a silty clay loam soil with moderate fertility and an electrical conductivity of 2.11 dS/m. Results revealed that alternate furrow irrigation significantly improved water usage efficiency and pod yield compared to conventional and fixed furrow systems. The highest cumulative pod yield (6.42 t/ha) and water productivity (2.40 kg/m³) were recorded under alternate furrow irrigation combined with the highest nitrogen level (480 kg N/ha). Increasing nitrogen levels led to marked improvements in vegetative growth, photosynthetic activity, and ultimately pod development, especially when supported by balanced fertilisation with phosphorus and potassium. The findings demonstrate that alternate furrow Irrigation, in conjunction with appropriate nitrogen fertilisation, can reduce irrigation water use by up to 35% while maintaining or enhancing okra yield. This integrated approach offers a practical and sustainable solution for improving crop productivity and resource use efficiency in fine-textured soils of arid and semi-arid regions.