2Irrigation Department, Shiraz University, Shiraz, I.R. of Iran
Development and use of crop growth models is an effective tool for agricultural planning and decision making in agricultural industry. Besides, the drought and limited supplies of water in many areas of the world has increased attention to favourable strategies in farm management such as efficient irrigation and planting methods. The objective of this study was to develop a crop model for safflower known as a multi-purpose crop under various irrigation regimes, planting methods and nitrogen fertilization. The experiment was designed as split-split plot that arranged in randomized complete blocks with irrigation strategy as the main plot, planting method as the subplot and nitrogen levels as the sub-subplot in three replications. The irrigation strategies consisted of ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI) as a partial root drying (PRD) technique. The planting methods were on-ridge planting (P1) and in-furrow planting (P2) methods. The fertilizer levels were 0 (N0), 100 (N1) and 200 (N2) kg ha-1 of urea as 0, 46 and 92 kg N ha-1. Two years of the experiment carried out in a semi-arid area from 2012 to 2014. The field data of the second year of experiment were used to develop the model and it was validated by the data of first year. The results indicated that the proposed safflower model is able to estimate evapotranspiration, soil water content, leaf area index, soil surface evaporation, crop transpiration, biomass, straw and seed yield of safflower in an appropriate manner. The safflower model is useful for having better field management and reducing administrative costs with respect to the model simplicity and its briefness in data input.