Normalized differential vegetative index as indicator of remote water stress in vineyard (Vitis vinifera L. cv. Cabernet Sauvignon)

Regulated deficit irrigation (RDI) is a technique of controlling irrigation in the vineyards to obtain benefits such as the reduction of water used, control of vegetative growth and berry quality. However, if the magnitude and duration of the water deficit are not monitored, stress may be applied, potentially leading to negative effects on the crop. To successfully carry out the management of the RDI, a series of proximal methodologies have been used that have facilitated decision-making based on indicators of the water status of plants and soil, however, considering the advances in precision agriculture, it is necessary to validate multispectral indicators that can be used as tools for farm-level water management. This study aimed to evaluate whether the normalized differential vegetative index (NDVI), measured remotely with a multispectral camera coupled to a drone, is related to the midday stem water potential (Ψs), in Vitis vinifera L. cv. Cabernet Sauvignon, during the phenological stage of fruit set, under RDI, to be used as an indicator of remote water stress. The main results of the study showed that: 1) in pre-fruit set states, there is no relationship between NDVI and Ψs; 2) once set is initiated, NDVI is significantly related to Ψs. Therefore, this indicator could be proposed as a remote tool for predicting the water status of the vineyard, specifically in this phenological state, facilitating the control of the RDI.