ESTIMATION OF CROP COEFFICIENT VARIATION THROUGH SATELLITE VNIR SPECTRAL DATA

Crop coefficient is a principle factor to estimate crop water consumption. Traditionally Kc estimated from Kc = ETc/ETo or from the FAO table. The aim of this paper is to develop a simple model to estimate Kc_NDVI using remote sensing technique. To develop such model this work was cared out in salhia area on three winter crops wheat, potato and sugar beet, on certain dates of their growing seasons of 2013-2014. Landsat 8 and Landsat7, the Enhanced Thematic Mapper Plus (ETM+) satellites were used to generate NDVI values on these dates. The values of NDVI and the Kc estimated from Kc = ETc/ETo were used to established Kc_NDVI equation. The following equation Kc_NDVI = 1.259 NDVI + 0.034 is the developed model with r = 0.92. To validate this model the values of Kc predicted using it at six dates on wheat and potato crops raised on same site on 2014-2015 growing season was compared with estimated Kc_FAO on same dates. The validation give a good results with r = 0.98 for the two crops.