Safflower (Carthamus tinctorius L.) yield as affected by nitrogen fertilization and different water regimes

Due to its origin and hardiness, safflower is usually cultivated in low-fertility soils with few inputs and no irrigation. In Brazil, little is known about its response to nitrogen (N) and irrigation. This study was carried out near the city of Engenheiro Coelho, SP, Brazil, in 2014, in order to determine the effect of increasing nitrogen application rates (0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 kg ha-1) on safflower cultivation under irrigation and rainfed conditions. The use of irrigation during drought periods allowed stress reduction and significantly increased yield components and grain yield. Safflower yield was influenced by the interaction between water regimes and nitrogen rates. Grain yield may vary depending on several factors, however, maximum yield was achieved with rates of 208 and 214 kg N ha-1 under irrigation and rainfed conditions, respectively. For oil yield, 200 kg N ha-1 were sufficient, regardless of the water regime.