Assessing plant water status: Part 1 - Classical methods

As a result of the changing climate, water scarcity poses a significant threat to crop and pasture production. Although soil water content can indicate drought, its measurements often provide limited spatial resolution and are weakly correlated with plant water status, producing misleading drought assessments. Accurately measuring plant water status is essential to understand nutrient uptake, thermal regulation and stomatal behavior. Water status, primarily determined by turgor pressure and its crucial component of leaf water potential regulate plant physiological functions. These variables depend on the energy state of water, determining essential processes such as stomatal conductance and cell expansion. Becaus directly measuring turgor pressure may be impractical, leaf water content and relative water content are reliable proxies for assessing water status. In Part 1 of a two-part review, we provide insights into using leaf water content as a reliable proxy for assessing water status and synthesize classical, destructive methods for measuring plant water status, encompassing gravimetric techniques, Scholander pressure chamber and psychrometric techniques. These classical approaches provide direct, physically interpretable and mechanically based measurements of water content, water potential and turgor-related parameters. Operational principles, procedural considerations and physiological insights accompany each method. These destructive measurements determine water status accurately, forming the essential calibration and validation backbone for modern non-destructive approaches discussed in Part 2. Integrating these classical measurements with concurrent soil moisture data provides reliable guidance for irrigation management, optimizing water usage and improving crop resilience in the face of increasingly variable climatic conditions. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.