Response of Winter Wheat to Co-Inoculation with Azotobacter and Arbescular Mycorrhizal Fungi (AMF) under Different Sources of Nitrogen Fertilizer

In order to evaluate the effects of inoculants and chemical fertilizer on quantitative and qualitative yield, a bread wheat cultivar treated with Azotobacter, arbuscular mycorrhiza fungi (AMF) and nitrogen sources by using split plot on the basis of randomized complete block design with three replications in Fars Agricultural Research Station during 2007-2008. Main plots consisted of nitrogen fertilizer sources, which were ammonium nitrate, ammonium sulfate, urea and SCU (Sulfur Coated Urea). Sub plots consisted of four treatments i.e. control, inoculation of arbuscular mycorrhiza fungi (AMF), Azotobacter chroococcum and dual inoculation of AMF + Azotobacter chroococcum (AMF + Azc). Results showed that the highest plant height was related to SCU fertilizer, resulting to lodging in some plots. The most spike per square meter was obtained by ammonium nitrate and urea fertilizers. Single application of Azotobacter and Mycorrhiza inoculation and in combination to each other increased significantly spike per square meter compared to without inoculation treatment. Ammonium nitrate and ammonium sulfate fertilizers produced more grain per spike than urea and SCU fertilizers. Also, interaction effects of biofertilizers and N sources were significant at 5% probability level in this trait. The highest value of kernel weight was obtained with urea and ammonium nitrate fertilizers and the lowest value was belonged to SCU fertilizer. Maximum kernel weight was found in Azotobacter and Azotobacter+Micorrhiyza and minimum in control and Micorrhiyza treatments. Ammonium nitrate and Azotobacter + Micorrhiyza treatments gave significantly higher grain yield than the other N sources and biofertilizers. Biologic yield and harvest index were only affected by N sources treatments. As, ammonium nitrate and urea fertilizer treatments were higher than two other N sources. Grain protein percent increased up to 19 % in ammonium nitrate than urea and SCU fertilizers. Azotobacter + Micorrhiyza treatment increased grain protein by 13 % than control. In general, results from the present study indicated that grain yield and yield components of wheat have been affected significantly by the inoculation with Azotobacter and Mycorrhiza. Also, ammonium nitrate and ammonium sulfate resulted in increasing grain yield and nitrogen fertilizer efficiency compared with urea and SCU.