Irrigation Scheduling Using Plant- and Soil-Based Methods

Over the last decades, many novel approaches to irrigation scheduling based on the use of sensors and new technologies have been proposed. These methods are based on the measurement of variables related to the plant or soil water status. Plant-based methods evaluate physical variables associated with plant response to water deficit and help in defining when irrigation is needed. However, the practical application is hindered by the sensitivity of water stress indicators to atmospheric demand and the low sensitivity to mild water deficits, so they are useless for preventing reductions in expansive growth. Soil-based methods include techniques measuring the water content or water potential of the soil, and they may provide indication on both when to irrigate and how much water to apply. Their main limitation lays on how to cope with the large spatial variability in soil water content.