Remote Sensing for Irrigation of Horticultural Crops

Abstract

This paper reviews the literature on applications of remote sensing for monitoring soil-and crop-water status for irrigation purposes. The review is organized into two main sections: (1) sensors and platforms applied to irrigation studies and (2) remote sensing approaches for precision irrigation to estimate crop water status, evapotranspiration, infrared thermography, soil and crop characteristics methods. Recent literature reports several remote sensing (RS) approaches to monitor crop water status in the cultivated environment. Establishing the right amount of water to supply for different irrigation strategies (maximization of yield or water use efficiency (WUE)) for a large number of crops is a problem that remains unresolved. For each crop, it will be necessary to create a stronger connection between crop-water status and crop yield.

A Review of Current and Potential Applications of Remote Sensing to Study the Water Status of Horticultural Crops

“…Manned high-altitude aircraft (operating within few km) and, more recently, UAS (operating under 120 m) filled the spatial gap between high-resolution ground measurements and relatively low-resolution satellite measurements [40,41]. In the context of water status estimation for horticultural crops, all the aforementioned remote sensing platforms are utilised depending on the user requirements [23,42,43]. Each remote sensing platform has its own advantage and shortcomings.…”

“…The bands are generally designated for the visible and NIR region with extended capabilities in SWIR, TIR, as well as red edge region ( Table 1). The most widely used band combinations to study the water status of vegetation are the visible, NIR and TIR bands [23,25,53,54]. With the plethora of satellite systems currently available, user requirements on band combination may be achieved by using multiple satellites.…”

“…Such processing can be a combination of atmospheric, radiometric, and geometric corrections, where applicable [57,58]. Furthermore, as the agricultural applications of the satellite imagery are illumination sensitive and weather dependent, conditions have to be optimal on the satellite revisit day to avoid data corruption due to, for example, cloud cover [23,53]. Cloud corrupted data (~55% of the land area is covered by cloud at any one time [59]) will require users to wait for the next revisit to attempt the data acquisition.…”

“…As a result, over-or under-watering can occur, which can lower yield and fruit quality [19][20][21][22]. This is especially evident for non-homogenous blocks where spatial variability of soil and water status is expected [23][24][25].…”

Agronomic Management for Enhancing Plant Tolerance to Abiotic Stresses—Drought, Salinity, Hypoxia, and Lodging

“…Soil water content is crucial for managing irrigation and can be measured by means of suitable sensors [52,53] or estimated by water balance models based on the continuity equation (conservation of water applied to the soil reservoir). These technologies allow for selecting irrigation time and volumes.…”