New proximal sensing technologies are desirable in viticulture to assess and map vineyard spatial variability. Towards this end, high-spatial resolution information can be obtained using novel, non-invasive sensors on-the-go. In order to improve yield, grape quality and water management, the vineyard water status should be determined. The goal of this work was to assess and map vineyard water status using two different proximal sensing technologies on-the-go: near infrared (NIR) reflectance spectroscopy and thermal imaging. On-the-go spectral and thermal measurements were acquired at solar noon, on east side of the canopy in a Tempranillo (Vitis vinifera L.) commercial vineyard. A spectrometer (1100-2100 nm) and thermal camera operating at 0.30 m and 1.20 m respectively from the canopy were mounted on a ATV which moved at 5 km/h. Midday stem water potential (Ψs) was used as reference method. Spectral, thermal and physiological measurements were acquired over several dates from July to September, in seasons 2015 and 2016. Partial least squares (PLS) was used as the algorithm for the training of the water stress spectral prediction models. In the cross- validation, all determination coefficients (R2) were above the 0.89 marks for Ψs. Moreover, canopy temperature and the crop water stress index (CWSI) were correlated to stem water potential (Ψs), with a R2 value of 0.79. Vineyard water status was mapped using both near infrared reflectance spectroscopy and thermal imaging technologies and enabled the identification and delineation of zones with homogeneous grapevine water status to steer precise and optimized irrigation schedules in the context of precision and sustainable viticulture. These results suggest that both near infrared reflectance spectroscopy and thermal imaging can be used to non-destructively assess and map the vine water status in commercial vineyards. In conclusions, both new sensing proximal technologies show the potential applicability for assessing and mapping of vineyard water status in precision viticulture.
