Estimating Tree Water Status in Apple Orchard using Reflectance in the Thermal Domain of Landsat 8 Satellite

In this study, the crop water stress index (CWSI) was monitored at a commercial apple orchard in Brandenburg (Germany). In this regard, two methods were applied; an established method based on canopy leaf temperature using infrared thermometers (IRT), followed by calculation of CWSI according to Idso $(CWSI_{IDSO})$. The established method was compared to satellite-based approach $(CWSI_{sat-based})$ using Landsat 8 satellite images. During the IRT measurements, the sampling for estimating vegetation water content (VWC) was carried out. The results showed that the average differences between CWSI estimation methods were less than 3%, indicating good agreement between both methods. There is a negative correlation between VWC and two CWSI, indicating CWSI
sat
has the potential to replace direct VWC measurements and to provide the tree water status that includes spatial distribution, through mapping of extended areas of the apple orchards, which may more effectively monitor water stress and irrigation scheduling