Assessing Water Stress Dynamics in Kenaf (Hibiscus cannabinus L.) Through the Crop Water Stress Index and Physiological Parameters

Abstract

The effect of water stress in kenaf was studied using the Crop Water Stress Index (CWSI). Relationships of the CWSI with various physiological parameters under different irrigation levels were determined. Field trials were conducted over 2 years under sub-humid climate conditions using a randomised block design with four irrigation treatments on the basis of soil water depletion. Physiological measurements including leaf water potential (LWP), chlorophyll reading (CR), leaf area index (LAI), net photosynthesis rate (A) and stomatal conductance (gs) were recorded throughout the growing seasons. Results showed significant variations in CWSI values among irrigation treatments, with a recommended threshold of 0.15 for optimal irrigation timing. Irrigation significantly affected LWP, CR, LAI, A and gs in each year, at the p < 0.01 level. Correlation analyses revealed strong relationships between CWSI and physiological parameters, indicating its potential to predict changes in plant physiology and dry matter yield of kenaf under water stress conditions. The study highlights the importance of optimising irrigation on the basis of CWSI to enhance crop resilience and productivity. By leveraging CWSI as a predictive tool, farmers can make informed decisions regarding crop physiology, irrigation timing and water management strategies to mitigate water stress and improve kenaf yield in a sustainable manner.