Zoning the plains of Salt Lake catchment for cultivation of four medicinal plant species based on climatic and hydrological indicators

Since Iran has always faced fluctuations and decreases in the rainfall, and on the other hand, the uncontrolled harvest of water resources have led to a more severe decline in the groundwater resources, the medicinal plants cultivation can help overcome the water deficit crisis. This study aimed at determining the ecological suitability of cultivation of four medicinal plants including damask rose (Rosa damascena Mill.), saffron (Crocus sativus L.), thyme (Thymus vulgaris L.), and lavender (Lavandula angustifolia L.) in 36 plains located in the Salt Lake (Namak Lake) catchment. The research methodology included the collection, reconstruction, and quality control of the information, climatic simulation, calculation of the agro-climatological indicators, and estimation of the agriculture share of water resources separately for each plain, estimation of the plant water needs, determination of the moisture balance, preparation of the suitability layers of cultivation, and finally overlaying the layers to produce the suitable/unsuitable agricultural lands for the cultivation of these plants. The climate simulation was performed by the strategic re-sampling technique to generate the different scenarios during the period 2011-2035. All the models under the different scenarios predicted a decrease in the rainfall and an increase in the maximum and minimum temperatures. The EC-EARTH model under the RCP2.6 scenario predicted the highest percentage of rainfall decrease (about 23%) and temperature increase. Due to the salinity and heat stress, the agricultural lands located at Sharifabad plain, northern parts of Qom-Kahak plain agricultural lands, eastern lands of Saveh plain, northern lands of Kashan plain, and southern lands of Varamin plain were unsuitable for the cultivation of all four medicinal species. The cultivation of saffron and damask rose in most of the plains of Salt Lake catchment was suitable or very suitable.