Estimation and determination of spatial pattern of Apple tree water requirement in Iran

Evaluation of water requirement in designing irrigation systems and water supply in agriculture is important. The aim of this study was to estimate and determine the spatial pattern of water requirement of apple tree using weather stations statistics from 1985 to 2013 in apple tree cultivation areas in Iran. Initially, annual reference evapotranspiration was estimated based on the FAO, Penman-Monteith model, In the following, the stages of growth the summer apple Kohanz crab and autumn apple Red-Delicious were identified. Eto calculation annual results and water requirement of growth stages were identified using ArcGIS10.2 as a spatial pattern for each variety. The results showed that the annual ETo in the North-Eastern and Southern regions of the apple cultivation area cultivar reaches more than 2000 mm. The summer apple Kohanz crab has less water requirement than autumn apple Red-Delicious varieties and the middle stage of growth in apple trees have the highest water requirement. The spatial changes in evapotranspiration and water requirement apple trees are due to altitude factor. From the north to the south and from the West to the East, the apple cultivation areas in Iran increases the amount of water requirement.