Effect of Biological and Chemical Phosphorus Fertilizer on Yield and Yield Components of Safflower (Carthamus tinctorius L.) under Low Irrigation Conditions

Regarding to limitation of water resources and the consequences of chemical fertilizers in terms of the environment, recognizing the affecting factors of crop production in limited water conditions is very important. In order to investigate the effect of chemical and biological phosphoric fertilizers on yield and yield components of safflower under different irrigations, an experiment was conducted as split plot based on randomized complete block design with three replications at the Agricultural College of Zabol University. The irrigation treatment included normal irrigation, discontinuation of irrigation intervals before and after flowering as the main factor and types of phosphorous fertilizers in 4 levels: control (no fertilizer), 100% chemical phosphorus fertilizer, 50% chemical phosphorus fertilizer + 50% biological phosphate (combined fertilizer) and 100% Biological phosphate fertilizer were sub factor. Based on the results of analysis of variance, plant height, number of main and minor branches and harvest index were significantly affected by different fertilizer treatments. Comparison of means showed that the highest amount of traits were belong to the combined treatment of chemical and biological phosphoric fertilizers which increased 1.2, 1.7 and 1.6 and 1.55 times, respectively. The results also showed that number of heads per plant, 1000 seed weight, biological yield, grain yield, chlorophyll and carotenoids were significantly affected by different fertilizer treatments, irrigation and interaction. The highest amount of these traits was observed in the combination of biological and chemical fertilizer under normal irrigation conditions, which increased 2, 2.4, 2.12 and 2.59, respectively, compared to the control fertilizer treatment, respectively. Also, the results showed that the application of pure fertilizers to improve the effective traits in safflower yield was lower than pure fertilizers in all irrigation treatments. The highest amount of carotenoids (5.57 mg.g-1FW) belonged to the combination of biological and chemical fertilizer in irrigation treatment after flowering. According to the results, it seems that the combination of chemical and biological phosphorous fertilizers in tolerance to drought conditions can play a significant role in safflower plants.