Developing crop canopy model for irrigation of high-density olive groves by using UAV imagery

Plant architecture is a key issue in understanding olive tree water needs. The aim of this study is to evaluate water requirements of a high-density olive grove by coupling an agro-hydrological model with UAV-based, high-resolution 2D imagery and 3D structure from motion (SfM) reconstruction. Three planting densities (1670, 1000, 500 trees ha-1) were drip irrigated according to two irrigation regimes. Evapotranspiration was estimated using FAO56 and FAO66-modified approaches. FAO66 input data (canopy volume and coverage) were quantified using manual ground-based surveys, 2D imagery and 3D SfM reconstruction. 2D imagery showed better relationships to ground-based area and volume estimates than the 3D SfM approach. Moreover, coupling the ET model with 2D data accurately predicted crop water needs.