Stress detection in vineyards using a low-cost terrestrial mobile system

Abstract

Stress detection in vineyards is typically performed using plant-based techniques such as stem water potential or leaf gas-exchange rate. However, these types of measures are not representative of the whole vineyard, because they are performed on selected points or a limited group of vines within the vineyard. In this context, canopy temperature (Tc) has been proposed as a sensitive indicator of plant water status. At the present time Tc can be evaluated quickly with portable infrared temperature sensors. These sensors can be integrated to microcontroller boards, incorporating global position information from miniaturized GPS. Therefore, it is possible to obtain Tc records and its spatial distribution in the vineyard simultaneously. In this study we describe a low cost terrestrial mobile system used for registering Tc in a vineyard plot trained on a vertical shoot positioned (VSP) system. To verify the suitability and sensitivity of the mobile system, stem water potential was measured in selected plants inside of the vineyard plot. As a result, the system allowed the creation of a grid with canopy temperature and position; with this data it was possible to elaborate maps that reflected the spatial variability in the vineyard plot. In order to develop plant water status maps, the crop water stress index (CWSI) was calculated. The results show that the areas with water restrictions were identified allowing the definition of different zones within the plot.