Estimation of Evapotranspiration and Crop Coefficient of Bunium persicume (Boiss.) in Khorram Abad Reagion

In order to reduce water consumption, the water requirement should be calculated and given to the plant based on its water requirement. One of the best approaches to assess plant water requirement is determination of crop evapotranspiration and coefficient, using lysimeters. Bunium persicume (Boiss.) is one of the important medicinal plants in Iran. In this study, an experiment was conducted at Agriculture Faculty of Lorestan University for one year to estimate the transpiration of the plant. In present research, Bunium persicume and reference grass plant were sown in micro Lysimeters. Each of the experimental units was irrigated, based on crop capacity and weighing method. According to the obtained results, the rate of evaporation and transpiration and yield of Bunium persicume species were 547 mm and 300 Kg/ha respectively. In this study, using the quadratic curve fitting on the lysometric data related to plant coefficient (Kc), the plant coefficient equation was obtained as a function of the days after planting for Bunium persicume species. The number of days in different stages of growth (first stage (primary), second (growth and development), third (middle) and fourth (final)) were 10, 30, 30 and 20 days. Finally, based on the FAO method, the crop coefficient (Kc) curves were drawn during different growth periods for both species and, in average, it was concluded that in four stages of plant growth, the KC values were 0.25, 0.43, 0.7 and 0.5 respectively. In general, by using the actual water requirement obtained and applying a precise irrigation schedule, it is possible to cultivate this crop in Khorram Abad region.