Determination of water requirement and vegetation coefficient of Carla (bitter melon) in Sistan region

Water is one of the most important factors limiting agricultural development in arid and semi-arid regions of the world. One of the most important issues in water management is to assess and determine the water requirement of plants. Water management, water resources and water requirements are essential for effective irrigation planning and efficient water resource management. In this way, Carla (bitter melon), which is the crop of the drug, were designed and tested in 2020 in dry climatic conditions using drained lysimeters and water balance methods. Four drainage lysimeters at the Agricultural Research Center were used for the experiment. Lysimeters of 50cm diameter and 120cm height were installed in the center of 25 × 20 m. Carla was planted in two lysimeters and in two lysimeters similar to the other reference plant (alfalfa). All planting operations were optimally performed and during the experiment it was tried to ensure that the soil moisture was not lower than the moisture content of the crop by timely irrigation so that the plant could not be subjected to moisture stress during the growing season. The experiment was conducted during a crop season from May 3 to July 27 for 88 days. Carla water requirement was determined between two consecutive irrigation intervals using soil water balance relationship. Carla water requirement was 915.15 mm during a experiment season. Also, the average coefficients of four stages of primary, developmental, intermediate and final growth in one experiment season were calculated 0.81, 0.915, 1.05, and 0.625, respectively.