The role of near-infrared sensors to measure water relationships in crops and plants

Water stress in plants is a complex physiological response to the limited availability of water to a plant. To address the variability in crop water status in different production systems, precision irrigation has been developed and implemented. Reliable measurements or predictions of plant water stress are desirable for numerous agricultural, forestry, conservation, and land rehabilitation applications. However, in order to implement precision irrigation, this method requires accurate information about the crop water status, soil moisture content, and weather (e.g., wind speed and vapor pressure deficit). Various technologies, including remote- and ground-based sensors, were developed, and some of them are available for the measurement of plant water stress. The objective of this article is to review the use of near-infrared (NIR) sensors to measure water potential in different crops and plants.