The interpretation of water consumption in the agricultural sector based on actual evapotranspiration

Determination of agricultural water consumption, as the main consumer of the country's water resources, is very important in order to plan and manage resource consumption and establish food security, water security and improve the livelihood of the growing population. Water consumption or actual evapotranspiration is the part of water used or delivered to the agricultural sector that is out of reach and cannot be reused. Estimating the spatial distribution of actual evapotranspiration (ETa) based on valid satellite data is a new approach in planning and determining water balance. In the study, amounts of actual evaporation, transpiration and evapotranspiration in the country and agricultural, horticultural and rainfed land uses were extracted using the methodology introduced by Food and Agriculture Organization (FAO), which is presented in the WaPOR database. The results showed that the highest actual evapotranspiration about 2500 mm occurs on the north coast and Lake Urmia. The results showed that the average amount of actual evapotranspiration in irrigated horticultural lands was 299.30 mm and in irrigated agricultural lands was 301.52 mm in a 12-year period. Accordingly, the amount of actual evapotranspiration of irrigated lands on a national scale and for the year 2018-2019 was calculated to 28.84 billion cubic meters, which is equal to 20.78 and 8.06 billion cubic meters for agriculture and horticulture, respectively. Furthermore, 72.1% of that belongs to transpiration and the other of that 27.9% belongs to evaporation.