Assessing soil and plant water status for irrigation management

Abstract

The study of the water relations of the soil-plant-atmosphere system (SPAC) is essential for the management and conservation of water in agriculture. A solid understanding of crop water relations was established many decades ago due to the fascination that so many scientists had with this subject matter. What has advanced more recently is the engineering and the technology that enable us to overcome the main limitations that existed in the quantification of water status within a dynamic SPAC. Spatial variability of soil-water properties is the main challenge for soil water assessment. The highly dynamic nature of plant water status and its variability within a field, and even within the plant, represent the main limitations for the assessment of plant water status. The need for the precise assessment of soil and/or plant water status is evident in two situations that are becoming more common. On the one hand, irrigation water scarcity leads to the adoption of deficit irrigation, a situation where crop water status monitoring is almost mandatory to avoid harmful water deficits. On the other hand, irrigation automation is being experimented under high-value crops in areas where water is expensive, as a mean ofconserving water and reducing costs beyond what can be achieved using conventional irrigation scheduling methods. The advantages and pitfalls of the many new methods proposed for such applications, relative to the established methods used in irrigation management, will be presented.