Potential of the Photochemical Reflectance Index in Understanding Photoinhibition and Improving Irrigation Water Efficiency in the Mediterranean Zone

Morocco's semi-arid region faces challenges due to limited water resources, necessitating efficient irrigation practices for sustainable agriculture. Precision agriculture, coupled with advanced technologies like the Photochemical Reflectance Index (PRI), holds great potential for optimizing irrigation water usage and enhancing crop productivity in this environment. This abstract provides a comprehensive overview of integrating precision agriculture techniques, PRI, and Net Radiation (R_n) to improve irrigation water efficiency and maximize crop productivity in Morocco's semi-arid zone. The study presents and analyzes an experimental investigation of the PRI signal in a winter wheat field throughout an agricultural season to comprehend its dependence on agro-environmental parameters such as global radiation (R_g) and R_n. R_n directly impacts the energy absorbed by plants, a crucial factor for photosynthesis. Elevated R_n levels generally increase energy availability for photosynthetic processes, resulting in higher chlorophyll fluorescence and PRI values. However, excessive R_n can lead to photoinhibition, damaging the photosynthetic apparatus and reducing photosynthetic efficiency. Understanding the interplay between net radiation, PRI, and photoinhibition is crucial for optimizing agricultural practices. Monitoring and managing net radiation levels allow farmers to ensure that the energy available for photosynthesis remains within the optimal range, minimizing the risk of photoinhibition while maximizing crop productivity. Additionally, the daily water stress index based on PRI (PRI_j), developed independently of structural effects related to leaf area index (LAI), showed a coefficient of determination (R²) of 0.74 between PRI_j and R_n. This reflects the extent of excessive light stress experienced by the wheat field throughout the experiment. In conclusion, the integration of precision agriculture techniques, specifically PRI, offers a promising approach to enhance irrigation water efficiency in Morocco's semi-arid zone. By employing this innovative tool, farmers can optimize water usage, reduce environmental impacts, and ensure the long-term sustainability of agriculture.