Smartphone as a tool for deficit irrigation management in Vitis vinifera  

Introduction

Vine water status is one of the most influential factors in grape vigor, yield, and quality (Ojeda et al., 2002; Guilpart et al., 2014). Severe water deficits during the first stage of crop development (bud break to fruit set) impact yield in the current year and the following year. While during grape ripening, water availability impacts berry size, grape composition, and health status. Therefore, a correct assessment of plant water status allows for proper water management with an impact on grape yield and composition (McClymont et al, 2012; Pereyra et al., 2022). Although there are direct or indirect techniques to assess the water status of a plot/plant, the reference technique remains foliar water potential (Carbonneau 1998). An alternative approach is to determine water status through the observation or evaluation of auxiliary variables related to water availability, such as the observation of growth apices. At this point, digital agriculture allows greater monitoring and predictability of crops, contributing to greater environmental sustainability. These digital tools become more necessary to adapt strategies to mitigate the effects of the climate change that is occurring and that intensely impacts grapevine cultivation (Venios et al., 2020). The climate outlook (2010-2070) for Uruguay and the region indicates an increase in rainfall (spring-summer) with longer periods of water deficits or excesses. In addition, they predict an increase of between 1.5 and 3.0ºC in the average temperature (PNA-AGRO, 2019) with a more significant number of heat waves. Heat waves are defined as more than three consecutive days with a maximum temperature higher than three times the standard deviation of the historical average expected for that date (PNA-AGRO, 2019). The evaluation of the growth apex or the determination of leaf area are input to characterize the water status within a vineyard during a given growth period and to adjust the water dosage to be applied.