The Effect of Water and Vegetation Vigor on Citrus Production in Egypt Using Remotely Sensed Data and Techniques

The vigor of vegetation and water availability are major components in agricultural production which are affecting on crop yield quantity and quality. Crop water stress occurs continuously over the total growing period or during any one of the individual growth periods of the crop. This study aims at quantifying the Vegetation and water stress effect on Valencia orange yield through remotely sensed data and techniques to predict the yield. Landsat OLI satellite imageries provide Red (R) and Near-Infra-Red (NIR) measurements which used to calculate the Normalized Difference Vegetation Index (NDVI). Land Surface Temperature (LST) was calculated from the thermal spectral region (band 10) and integrated with air temperature measurements to estimate Crop Water Stress Index (CWSI). Three Valencia orange farms were studied and 27 samples were collected (9 samples/farm). Two cultivation seasons data sets were investigated (2013/2014 and 2014/2015). Many regression models were produced. NDVI and CWSI were modeled with yield through a regression model analysis. The first season multi-regression model was the best model where R2 was high as 0.852 and regression validation was very good. The predicted yield map showed the spatial distribution of Valencia orange yield in the field, which ranged from 6.9 (ton/fed) to 29.2 (ton/fed).