Effect of Phosphate Solubilizing Bacterium, Arbuscular Mycorrhizal Fungus and Chemical Phosphorus Fertilizer on the Yield and Yield Component of Maize (Zea mays L.) under Normal and Limited Irrigation Conditions in the Karaj Region

In order to evaluate the effect of balanced application of chemical phosphorus fertilizer and seed inoculation with phosphate solubilizing bacterium and arbuscular mycorrhizal fungus and on the yield and yield components of maize (Zea mays L.) under normal and limited irrigation conditions, a split-split plots arrangement based on randomized complete block design with three replications was conducted. Treatments consisted of two levels of irrigation including: irrigation of 60 (normal irrigation) and 120 (limited irrigation) mm evaporation from class A pan evaporation; combination of phosphate solubilizing microorganisms (arbuscular mycorrhiza fungus and phosphate solubilizing bacterium) at four levels; and phosphate chemical fertilizer at three levels includes: no consumption of phosphate chemical fertilizer (control), consumption of 50% triple superphosphate fertilizer needed based on soil-test results and consumption of rock phosphate (based on the quantity of consumed phosphate of triple superphosphate source). The results showed that the irrigation levels had significant affect on all traits except harvest index, and the phosphate solubilizing microorganisms had significantly affected all traits except harvest index and number of row in ear. The results of mean comparison indicated that the maximum of amount most traits related to normal irrigation treatment, and co-application of phosphate solubilizing bacterium-arbuscular mycorrhizal fungus. The effect of phosphate chemical fertilizer on all traits was significant. Results of interactions between irrigation and phosphate solubilizing microorganisms in both normal irrigation and limited irrigation conditions showed that the co-application of phosphate solubilizing bacterium-arbuscular mycorrhizal fungus increased grain yield more than other treatments; Also, the result of balanced application of phosphate chemical fertilizer with phosphate solubilizing microorganisms showed that effect of balanced application of triple superphosphate fertilizer along with phosphate solubilizing microorganisms on investigated traits was more than rock phosphate