Estimation of the evapotranspiration and crop coefficient of Chamomile (Matricaria chamomilla L.) and Cumin (Cuminum cyminum L.) in Khorram Abad region

Determination of the water requirement and crop evapotranspiration is essential for each region of Iran( because of the value of water). One of the best approaches to assess plant water requirement is the determination of the crop evapotranspiration and coefficient, using lysimeters. Chamomile and cumin are two important medicinal plants in Iran. In this study, an experiment was conducted at the Agriculture Faculty of Lorestan University for one year to estimate the transpiration of these two plant species. In the present research, these species and reference grass seeds were sown in mini Lysimeters. Each of the experimental units was irrigated, based on crop capacity and weighing method. The results showed that the amount of evapotranspiration for chamomile was 610.3 mm for production of 780 Kg/h, and for cumin, evapotranspiration was 416.4 mm for production of 300 Kg/ha, respectively. 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 for chamomile were 0.16, 0.54, 0.86 and 0.50 and for cumin they were, 0.14, 0.52, 0.7 and 0.5, respectively.