Determining Water Requirement and Crop Coefficient of Date Palm cv. Barhee in Khuzestan Province

The amount of agricultural water consumption and water waste can be reduced by properly adjusting the irrigation schedule of plants based on the precise determination of the water requirement of each plant. This research was carried out to determine water requirement and crop coefficient of Barhee date palm. Three drainage lysimeters were applied to measure date palm evapotranspiration. The amounts of date palm evapotranspiration and reference evapotranspiration were calculated using soil water balance equation and Penman-Monteith method, respectively. The results showed that water requirement of 6, 7, and 8 years old date palm were 1493, 1613 and 1695 mm, respectively, while the amounts of reference evapotranspiration were 2070, 1950, and 1945 mm, respectively. The amount of date palm water requirement increased by 8%, for 6 to 7 years-old  and 7.8% for 7 to 8 years. The crop coefficient of 6 years old date palm varied in the range of 0.54-0.80. The minimum crop coefficient was in November, while the maximum was in June and July. For the 7 and 8 years old date palm, crop coefficient varied in the range of 0.62-0.97 and 0.47-1.01, respectively. In 7 and 8 years old date palm, the minimum crop coefficient was in November and the maximum was in August.