How thirsty the crops are: Emerging instrumentation for plant-based field measurement of water stress

To grow crops in areas with arid climates, porous karst soils, or increasingly unpredictable seasonal droughts, farmers struggle for their yield and spend precious water resources on irrigation. This ecological and economic problem of excessive water usage in agriculture may be alleviated by application of precision irrigation techniques. Precision irrigation implies precise spatial and temporal control of water supply based on the actual water demand. This is also critical for maximizing the yield-quality of cultivars like grapevine, which dynamically change their water requirements throughout different parts of their vegetative season [1].

Measuring the Water Demand in Precision Irrigation

Measurement techniques used for irrigation scheduling are usually grouped into three categories. The first category is soil-based irrigation scheduling, relying exclusively on either measurement or estimation of soil-water status. The second are plant-based irrigation techniques, determining the water-demand based on measured plant's water status. Finally, the third category contains combined techniques, combining both soil-water and plant-water status measurements.