Study on the effects of Nitrogen and Phosphorus fertilizers on Safflower varieties yield and oil content in dry lands

In order to determine the effects of different levels of nitrogen and phosphorus fertilizers on the yield and oil content of new safflower genotypes, a study carried out in tow different dryland research stations (Maragheh and Sararood,) in Iran. The experiment was arranged with four nitrogen fertilizer levels (0,30,60,90) kg.ha-1 and three phosphorus fertilizer levels (0,30,60) kg.ha-1 with tow Safflower Genotypes ( V1=No36 and V2=79-299) in Maragheh and (V1=537598 and V2=S-541) in Sararood in factorial RCBD with three replications. Nitrogen fertilizer was supplied as urea and phosphorus as triple super phosphate. In each year, the crop harvested after maturity and mean yield analyzed statistically. In Maragheh, the results indicated that increasing nitrogen fertilizer increased the grain and biomass yield but phosphorus did not affect the yield .In the interaction effect of safflower variety with nitrogen and phosphorus fertilizers, application of V2N90P60 had the highest seed grain yield (961 kg.ha-1) and treatment V2N90P0 had the highest biomass yield (4173 kg.ha-1). In Sararood, increasing nitrogen fertilizer did not increase seed yield but it increased plant height. In interaction of nitrogen and phosphorus fertilizers, application of N60P30 had the highest grain yield (1283 kg.ha-1). It can be concluded that safflower grain yield differed at different levels of Nitrogen fertilizer in Maragheh regions. However, phosphorus fertilizer did not increase safflower grain yield in Maragheh and Sararood. Regarding the amount of precipitation and yield in different years, application of 90 kg.ha-1 Nitrogen fertilizer together with 30 kg.ha-1 phosphorus (N90P30) is recommended in Maragheh regions and application of 60 kg.ha-1 Nitrogen fertilizer together with 30 kg.ha-1 phosphorus (N60P30), is recommended in Sararood dry lands for safflower production.