Estimating Crop coefficients and evapotranspiration for Calendula officinalis L. in a arid climate in Iran

Calendula officinalis L. is a medicinal plant used for manufacturing skin and beauty medication products. Estimating Calendula officinalis L. water requirement, crop evapotranspiration (ETc) and crop coefficient (Kc) are among the areas indeed requiring more research. This study was conducted to calculate Calendula officinalis L. crop coefficients (Kc) and crop evapotranspiration (ETc) because the water scarcity problem in semi-arid regions; in which management of water resources is a vital issue. This study was conducted in Kerman, a city in southeast of Iran with semi-arid climate. In order to estimate the crop evapotranspiration, six lysimeters was used. The Calendula officinalis L. were grown in five lysimeters, and the grass reference crop was grown in a lysimeter. Moreover reference evapotranspiration (ETo) has been calculated using Penman-Monteith method, and was compared with the ETo obtained from lysimeter. The Calendula officinalis L. water requirement for the result obtained from lysimeter were 335.72 mm for 2014 and 1043.72 mm for 2015 years; also the reference water requirement obtained from lysimeter and Penman-Monteith method was 769.46 and 746.71 mm, for 2014 year and 1767.76 and 1424.8 mm for 2015 year, respectively. In this study the estimated Calendula officinalis L. crop coefficients in different growth stages were 0.71, 1.21, 1.48 and 0.66 for 2014 and 0.84, 1.21, 1.57 and 1.08 for 2015, respectively.

Keywords:

Calendula officinalis L. , lysimeter , medical plants , crop coefficients , Evapotranspiration