Response of Spring Safflower to Co-Inoculation with Azotobacter chroococum and Glomus intraradices Under Different Levels of Nitrogen and Phosphorus

Abstract

Problem statement: In order to evaluate the effects of co-inoculation of Azotobacter and Mycorrhiza with nitrogen and phosphorus levels on yield and yield components of spring safflower, this study was carried out in the experimental field of Farahan University in Markazi province- Iran in 2006. Approach: A factorial experiment in the form of complete randomized block design with three replications has been used. Inoculation of Azotobacter (without and with inoculation by Azotobacter chroococum) and Mycorrhiza (without and with inoculation by Glomus intraradices) under different levels of nitrogen and phosphorus levels [F₀ = N₀+P₀(kg ha^-1), F₁ = N₅₀+P₂₅(kg ha^-1), F₂ = N₁₀₀+P₅₀(kg ha^-1) and F₃ = N₁₅₀+P₇₅(kg ha^-1)] on spring safflower (Carthamus tinctorius L.-cv. IL-111) have been studied. Results: In this study some characteristics such as: Harvest index, hectolitre weight, root dry weight, seed yield, mycorrhizal root colonization, number of days to maturity were assessed. Results indicated that treatment (A₁M₁F₂) with average grain yield 1239 (kg ha^-1) and treatment (A₀M₁F₀) with average grain yield 723.7 (kg ha^-1) were significantly higher than other treatments. Seed inoculation at the planting date with Azotobacter and Mycorrhiza caused increasing grain yield about 6.13% in compare with control treatment. Conclusion: Seed yield and yield components of safflower have been affected significantly by the inoculation with Azotobacter and Mycorrhiza, because these biofertilizers can fix atmospheric nitrogen and increase phosphorus availability in soil and enhanced absorb elements by safflower.