Effect of phosphate solubilization microorganisms(PSM) and plant growth promoting rhizobacteria (PGPR) on yield and yield components of corn (Zea mays L.)

In order to study the effect of phosphate solubilization microorganisms (PSM) and plant growth promoting rhizobacteria (PGPR) on yield and yield components of corn (Zea mays L.) cv. SC604 an experiment was conducted at research farm of Agriculture College located at Sari، Iran during 2007. Experiment laid out as split plot based on randomized complete block design with three replications. Three levels of manures (consisted of 20 Mg. ha-1 farmyard manure، 15 Mg. ha-1 green manure and check or without any manures) as main plots and eight levels of biofertilizers (consisted of 1-NPK or conventional fertilizer application; 2-NPK+PSM+PGPR; 3-NP50%K+PSM+PGPR; 4-N50%PK+PSM+PGPR; 5-N50%P50%K+PSM+ PGPR; 6-PK+PGPR; 7-NK+PSM and 8-PSM+PGPR) as sub plots were treatments. Results showed that farmyard manure application increased row number، ear weight، grain number per ear، grain yield، biological yield and harvest index compared to check. Furthermore، using of PSM and PGPR in addition to conventional fertilizer applications (NPK) could improve ear weight، row number and grain number per row and ultimately increased grain yield in green manure and check plots. According to results in all fertilizer treatments application of PSM and PGPR together could reduce P application by 50% without any significant reduction of grain yield. However، this treatment could not compensate 50% reduction of N application.