Effects of Azospirillum and Azotobacter on yield and yield components of barley (Hordeum vulgare L.) under various levels of cow manure application

To study the effect of biofertilizers and manure on yield and yield components of barley (Hordeum vulgare) an experiment was conducted at Research Farm of University of Zabol، Iran in 2012 cropping season. Experimental treatments were arranged in a factorial design based on a randomized complete block design with three replications. Treatments were three manure levels (control، 20 ton/h-1، 30 ton/h-1) and four levels of biofertilizers (control، Azospirillum، Azotobacter and Azospyrilium+Azotobacter). Results indicated that manure levels had a significant effect on plant height، spike length، number of seed in spike and number of spike in plant. Biofertilizers caused significant differences in all measured traits expect for harvest index. The interaction effects showed that integrated application of manure and biofertilizers were more effective on barley growth. The highest economical yield (2. 6 ton/h-1) was detected in 20 ton/h-1manure + Azospirillum and Azotobacter application. Integrated application of manure and biofertilizers could significantly increase seed yield and yield components of barley.