Soil-Plant-Atmosphere Continuum (SPAC) is characterized by complex structures and biophysical processes acting over a wide range of temporal and spatial scales. Moreover, in olive groves, the plant adaptive strategies to respond to soil water-limited conditions make these systems even more complex. One of the greatest challenges in hydrological research is to quantify changes in plant water relations. A new promising technology is represented by field spectroscopy. New detectors, characterized by very high resolution and operating over a spectral range variable between 300 and 2500 nm, allow detecting narrow reflectance or absorbance peaks, separating close lying peaks and discovering new information, hidden at lower resolutions. The general objective of the research was to investigate on the pressure-volume (P-V) curve of olive trees in a non-destructive and repeatable way, as well as to propose methodologies aimed to parameterize the different compartments characterizing the SPAC system (soil or plant). Hyper-spectral data were used to characterize the hydraulic P-V curve of olive leaves, as well as to estimate, indirectly, the two main components of leaf water potential, i.e. turgor and osmotic potentials.