Canopy infrared thermography for water stress assessment in fruit crops

Efficient irrigation management is vital for optimizing water use in fruit crops, enhancing both yield and quality while conserving valuable water resources. Infrared thermography (IRT) has become a valuable non-invasive method for assessing plant water status providing real-time insights that facilitate more accurate irrigation decisions. This comprehensive review examines the role of IRT in managing irrigation for fruit crops. By capturing thermal images of crop canopies, IRT allows for the visualization of temperature variations linked to water deficiency, facilitating timely and accurate irrigation adjustments. Despite its potential, practical implementation of IRT faces challenges such as environmental variability, canopy heterogeneity, and the need for calibration across crops and conditions. Various thermal indices including Stress Degree Days (SDD), Crop Water Stress Index (CWSI), Degrees Above Canopy Threshold (DACT), Time Temperature Threshold (TTT) and Temperature Stress Day (TSD), are employed to evaluate plant water stress under field conditions. The consistent monitoring and interpretation of these indices during critical growth stages supports informed decision-making for irrigation management. This review contributes to the understanding of how IRT-based thermal indices can enhance precision irrigation and improve water use efficiency in fruit crops.