Evaluation of Nitrogen Efficiency Indices in Safflower Genotypes under the Influence of Different Nitrogen ‎Sources in Rainfed Conditions

Application of Azotobacter as a substitute or suitable companion of nitrogen chemical fertilizer with higher efficiency of inputs in safflower plant as a plant adapted to different climates is one of the sustainable agricultural strategies. Therefore, in order to study the effects of Azotobacter chroococcum and nitrogen fertilizer on nitrogen uptake, grain nitrogen and straw, nitrogen efficiency indices and grain yield of six safflower genotypes under rainfed conditions, a factorial experiment has been conducted based on a randomized complete block design with three replications in during growing season of 2015-2016 and 2016-2017 at the Agricultural Research Station Sarableh in Ilam Province. Experimental factors inoculate a combination of seed inoculation with Azotobacter chroococcum with urea chemical fertilizer application at four levels (non-inoculated with Azotobacter chroococcum and urea as control, seed inoculation with Azotobacter, inoculation with Azotobacter chroococcum + 50 Percent N from urea, and inoculation with Azotobacter chroococcum + 100% N from Urea) and six genotypes of safflower. The combined analysis of variance for two years show that the main effects of nitrogen source and genotype and also year× nitrogen source have had significant effect on all of the measured traits and nitrogen efficiency indices. The results from comparison of means show that inoculation treatment with Azotobacter chroococcum + 50% nitrogen fertilizer had higher Nitrogen use efficiencythan 100% nitrogen fertilizer use, with no significant difference in grain yield between the two treatments. Sina genotype with the highest grain yield and nitrogen use efficiency, compared to other genotypes, is more desirable for cultivation in rainfed conditions of the region.