Quantifying Saffron (Crocus sativus L.) Leaves and Corms Growth under Natural Saline Conditions

Saffron is one of the most important industrial water-efficient crops with high economic benefits. However, this precious crop is planted mainly in semi-arid regions, which usually suffer from both fresh water scarcity and soil salinity. Under saline conditions, simulation models help in understanding the crop growth and development. In this pot experiment, quantitative response of saffron was studied to find out if it can be irrigated with brackish water. The experimental treatments were consisted of a tap water (as a control with EC of 0.5 dS m(-1)) and six natural salinity levels of 1.5, 2, 3, 4, 5, and 6 dS m(-1). The effect of imposed salinity levels on three main parameters of vegetative stage of saffron including leaves fresh weight, corm weights, and numbers of daughter corms was then investigated. Accordingly, four macroscopic salinity models were applied and their performances were analyzed. Results for aerial parts (leaves) fresh weight indicated that the van Genuchten and Hoffman model with r and NSE values of 0.99 and 0.83 had higher accuracy than the other three models. Homaee et al. model with r = 0.96 and NSE = 0.72 performed best for the corm weight. For the daughter corm multiplication variable, the Homaee et al. model (r = 0.96, NSE = 0.79) provided a better estimation than the other models. Finally, the measured salinity threshold values of saffron under different growth stages were obtained for the first time. Accordingly the salinity threshold values of Saffron corms and leaves were obtained to be 1.2 and 1 dS m(-1), respectively. Thus, these findings can be used for initiating quantitative studies on saffron production under saline conditions.