Determination of Crop Coefficient of Narcissus Flower by Lysimeter method in Birjand Plain

Crop coefficient is one of the most important factors in irrigation planning and optimal allocation of water resources to plants. The crop coefficient is obtained through the ratio of actual evapotranspiration to reference crop evapotranspiration. In this research, in order to determine the crop coefficients of Narcissus flower, which is an important ornamental plant, an experiment was conducted during 2018 growing season using lysimeters, in Birjand. Three lysimeter was used in this project and water requirement of Narcissus flower was calculated by water balance method. Turf grass with a height of 12 cm was used to determine reference crop evapotranspiration. The base crop coefficients were obtained as 0.42, 0.85, 0.86, and 0.74, and the coefficients of the soil surface evaporation were 0.49, 0.28, 0.25 and 0.22 at, respectively, primary, developmental, middle, and end stages. Finally, the values of Narcissus flower’s crop coefficients at different stages of growth including primary, developmental, middle, and end stages were calculated as 0.91, 1.13, 1.11, and 0.96. The estimation of water requirement and irrigation management of Narcissus flower will be possible using the obtained Kc values.