Modification of the saffron model for growth and yield prediction under different irrigation water salinity, manure application and planting methods

The Saffron Yield Estimation Model (SYEM) was modified for salinity conditions, cow manure application and planting methods using two-year experiments data in Badjgah region of Iran. A split-split plot arrangement was conducted in complete randomized block design during two years with irrigation water salinity levels (0.45 (fresh water, S1), 1.0 (S2), 2.0 (S3) and 3.0 (S4) dS m-1) as the main plot, cow manure levels (30 (F1) and 60 (F2) Mg ha-1) as the sub plot and planting method (basin (P1) and in-furrow (P2)) as the sub-sub plot in three replications. Data of the second and first growing season were used to calibrate and validate the modified model, respectively. In the modified SYEM model, the soil salinity was estimated. Based on the NRMSE and d indices, the modified SYEM model presented a very good to fair estimation of actual evapotranspiration, evaporation, transpiration, soil water content and salinity, leaf dry matter, corm and saffron yields. The advantage of this model is its simplicity and easy calibration in other climate conditions for saffron crop. Prediction of saffron yield by this model can be used for better irrigation salinity management under different manure application levels and planting methods.