THE EFFECTS OF DIFFERENT SOURCES OF PHOSPHOROUS AND ITS SOLUBILIZING BACTERIA ON GROWTH OF THE HYBRID CORN (KSC 704)

To study the effects of phosphorous of different sources and its solubilizing bacteria on the corn growth an experiment was conducted at Miyandoab Agricultural and Natural Resources Research Station in 2005 in Iran. The arrangement of experiment was factorial based on RCB design with three replications. Treatments consisted of four levels of phosphate solubilizing bacteria: control, thiobacillus bacteria, phosphate solubilizing bacteria and Thiobacillus bacteria and phosphate solubilizing bacteria and three levels of fertilizer: without fertilizer, rock phosphate and triple super phosphate. In this study 0.5 m2 of each plot was sampled every 15 days intervals and were studied the dry matter per unit area (TDM), leaf area index (LAI), crop growth rate (CGR) and relative growth rate (RGR) were analyzed. The results showed that the application of thiobacillus bacteria + phosphate solubilizing bacteria + triple super phosphate increased total dry matter (TDM) and crop growth rate (CGR), while relative growth rate (RGR), decreased. LAI increased slowly during early growing stage but increased rapidly when growth proceeded. The highest LAI (4.3), TDM (3451 gr/m2) and CGR (5.41 gr/m2) were obtained from the application of thiobacillus + phosphate solubilizing bacteria triple super phosphate. Similar results were obtained by the application of thiobacillus + phosphate solubilizing bacteria + rock phosphate. It seems that application of thiobacillus + phosphate solubilizing bacteria is useful for availability of phosphorous to plant. Also, application of rock phosphate, due to low cost, availability of phosphorous to plant and its decreased effect on environment pollution can be used instead of other sources of phosphate fertilizers such as triple super phosphate.