Determination of evapotranspiration and crop coefficient of olive in different growth stages using remote sensing techniques and moisture balance in Tarom Zanjan

In horticultural plants¡ determining of evapotranspiration because of The existing problems in the direct measurement such as installing large lysimeter or the exact equipment and length during tree growth¡ often estimated indirectly and on the basis of meteorological data. With regard to the spatial variability of meteorological parameters and sometimes inappropriate distribution of meteorological stations estimating evapotranspiration is not possible with sufficient accuracy. Therefore use of procedures such as the remote sensing methods that consider these changes is best. In this study¡ evapotranspiration of olive trees were measured and determined with direct and indirect methods in two growing seasons 1393 and 1394 in Tarom district of Zanjan at different development stages. The actual evapotranspiration were determined by direct method¡ By measuring the moisture balance components and in the indirect method with help from the satellite imagery of landsat 8. Then by determining of the reference crop evapotranspiration¡ olive crop coefficient were calculated and were compared and evaluated. The results showed that calculated evapotranspiration and plant coeffiecient of remote sensing mehod in various olive growth stages matched with moisture balance data. So that¡ evapotranspiration correlation coefficient was 0.73¡ 0.87 and 0.82 for first¡ second and cumultative year¡ respectively. Moreover¡ correlation coefficients of plant coefficient was 0.95¡ 0.62 and 0.86¡ respectively. It is concluded that remote sensing method can be useful to estimate evapotranspiration of olive tree.