Rainfall and its distribution influences on rain-fed saffron yield and economic analysis

Spatial and temporal variability of precipitation events and rainfall depth are the major uncontrolled inputs in planting rain-fed crops and the prediction of their annual yield. Saffron ( Crocus sativus L.) is a strategic crop in Iran and due to its low water requirement and high income is considered in sustainable agricultural strategies. This study was carried out using a dataset from an 8-year rain-fed saffron experiment conducted in Bajgah region (Fars province), Iran. The objective was to determine the effects of annual rainfall, its distribution, and air temperature on saffron yield, and to determine the critical rainfall periods for rain-fed saffron yield. Also, economic analysis was considered for the saffron yield in the study region. Results showed that saffron yield cannot be predicted with adequate accuracy by the annual rainfall. Instead, fall and winter seasonal indices and annual index can be used to predict the rain-fed saffron yield when combined with saffron age and mean maximum daily air temperature in the given season. Results also indicated that rain-fed saffron yield is reversely related to the maximum daily air temperature in winter since warm winter causes the leaves to wither earlier and shortens the vegetative growth period. Internal rates of return for interest rates of 4, 8, and 12% were 30.9, 56.7, and 95.9% respectively which is economically feasible for rain-fed saffron production in the study area.