Integrated Fertilization Systems Enhance Quality an d Yield of Sunflower ( Helianthus annuus L.)

Abstract

Effects of various fertilizers such as farmyard man ure (FM), urea, and plant growth promoting rhizobacteria (PGPR, including the genera Azotobacter and Azospirillium ) were checked on yield, fatty acids, protein, and oi l contents of sunflower. A two-year field experiment was conducted in a semi-arid region in I ran in 2007 and 2008. The experiment was a split plot in a randomized complete block des ign with three replicates, with five fertilizer treatments as the main plots and two PGP R treatments as sub plots. Results demonstrated that the integrated fertilizers signif icantly increased the leaf area index, plant height, grain production, biomass, oil yield, and protein content in comparison with organic or chemical fertilizers. The maximum and mi nimum oil contents were obtained by applying 100% farmyard manure (F1) and 50% FM + 50% chemical (F3), respectively; however, opposite results were observed for protein content. When higher FM rates were used with PGPR, the saturated fatty acids (palmetic and stearic acids) declined significantly, while unsaturated ones (linoleic and oleic acids) were increased. The highest contents of linoleic acid (52.6%) and oleic acid (3 9.8%) were observed in F 3 and F 1 treatments, respectively. Bacterial inoculation als o increased the leaf area index, plant height, biomass, grain and oil yields, oil and prot ein contents up to 12, 3.7, 7.8, 10, 6.5, 5.6 and 5%, respectively.