Vineyard irrigation scheduling based on airborne thermal imagery and water potential thresholds

Abstract

Background and Aims Mapping the spatial variability of vine water status within a vineyard is necessary for the efficient management of irrigation water. The objective of this study was to determine whether estimates of remotely sensed leaf water potential (Ψrem) could be employed as a precise tool for scheduling irrigation at the irrigation sector level throughout the season. Methods and Results Three irrigation treatments were applied in a 16‐ha commercial vineyard to analyse the performance of the proposed methodology for monitoring regulated deficit irrigation strategies, and to evaluate the required frequency of the acquisition of thermal images for irrigation scheduling. An aircraft equipped with a thermal sensor flew over the vineyard throughout the season, and the averaged Ψrem of each irrigation sector was used as the irrigation trigger. The acquisition of about five or six Ψrem maps over the season is recommended. The starting date for acquiring thermal images depends on canopy vegetation size and on the difficulty of extracting pure vegetation pixels. The effect of acquiring thermal imagery on days after rainfall or with low vapour pressure deficits affected the estimation of Ψrem, and these constraints need to be considered for feasible irrigation purposes. Conclusions Remotely sensed leaf water potential was successfully used as an irrigation trigger to adopt regulated deficit irrigation strategies without any negative effect on yield and wine composition. Significance of the Study This study presented a promising and powerful method for scheduling irrigation throughout the season at vineyard level based on estimates of remotely sensed leaf water potential.

Airborne Thermal Imagery to Detect the Seasonal Evolution of Crop Water Status in Peach, Nectarine and Saturn Peach Orchards

“…A linear NWSB was developed in this study for peach trees using all season data of two following years (Figure 2d). This NWSB was similar to those reported for other crops such as olive and sweet lime trees, but completely different than other crops (Table 4 [5,20,21,[34][35][36][37]). Mandarine and orange trees were the only crops that reported a higher intercept of the NWSB than peach trees [21].…”

“…Remote sensing technologies are a successful tool to accurately identify spatial heterogeneity and have been shown to have the capacity to monitor irrigation at orchard level [4,5]. The use of remote sensing in the assessment of crop water status through canopy temperature has had a long development history.…”

Integrating Wheat Canopy Temperatures in Crop System Models

“…Such temperature anomalies impact the simulation of crop development and physiological processes and, therefore, need to be considered in crop system models. The canopy temperature of wheat is directly related to its water status [24][25][26][27][28]. We therefore hypothesize that environmental variables available from widely applied crop system models, such as daily transpiration and soil evaporation, allow for approximating wheat canopy temperatures.…”

The future of Earth observation in hydrology

“…For hydrological applications, SfM provides information on microtopography and can be used to generate digital terrain models (DTMs) and digital surface models (DSMs) at unprecedented detail. Apart from their natural affinity to application in precision agriculture (Zhang and Kovacs, 2012) and for vegetation health and stress monitoring (Zarco-Tejada et al, 2012, 2013, a number of recent contributions have demonstrated the utility of UAVs in hydrological process studies, with snow depth retrieval (Vander Jagt et al, 2015), flood mapping (Feng et al, 2015), irrigation monitoring (Bellvert et al, 2016), and evaporation estimation (Hoffmann et al, 2016) all being explored.…”