Lysimertic determination of crop coefficient and evapotranspiration of date palm in the fourth and fifth years of growth

The date palm area and fruit production in Iran are 253697 hectares and 1223142 tons, respectively. According to the Food and Agriculture Organization (FAO), Iran has ranked second in the world in date cultivation and production. Accurate planning is important for optimized use of water resources in the agricultural sector of Iran. The Basis for this planning is determination of water requirements of plants. The irrigation program can be adjusted correctly, the optimal amount of water can be provided for the plant, and  a few other problems such as excess watering or water stress can be prevented by accurate specifying of plant water requirement. The most common direct method for determining evapotranspiration is to use the principle of water balance in a controlled volume of soil or lysimeter. In lysimeter, conditions of water, soil and plant are determined more accurately than in the soil’s natural environment (Tripler et al., 2011). This research was carried out to determine the precise amount of crop coefficient and evapotranspiration of Barhee date palm in the fourth and fifth years of growth.