Application of leaf water content measurement to improve herbicide efficacy for effective weed management in a changing climate - A review

Climate change intensifies the impact of weeds, posing a significant threat to sustainable crop production and food security on a global scale. Weeds are more adaptable and resilient compared to crop species under climate change. Climate change complicates the effectiveness of weed control methods, leading to continuous decline in efficacy of herbicides, demanding more precise and site-specific herbicide application to address the evolving challenges. Leaf water content (LWC), a fundamental eco-physiological trait, serves as a key indicator of climate change effects and exhibits a strong correlation with herbicide efficacy. Assessing leaf water status of weeds can advance weed management. Different methods such as traditional gravimetric techniques, non-destructive techniques and modern remote sensing techniques for LWC estimation have modernized the measurement of LWC. Advanced methods now enable field application for real-time estimation of LWC, thereby enhancing potential for application in weed control practices. An integrated approach that combines various remote sensing technologies could provide the most comprehensive method for non-destructive, real-time LWC measurement. The development of better calibration models, integration of LWC measurements into predictive models for weed control efficacy, and refinement of remote sensing technology can help to precise weed control under changing climate. This article provides comprehensive review of impact of climate change on weeds and efficacy of weed control methods, role of LWC in enhancing weed management, and diversity of technologies used for monitoring LWC. Integrated weed control based on LWC measurement can significantly reduce herbicide pollution, ensure sustainable weed management, and minimize crop yield losses.