PHOSPHATE SOLUBILIZING BACTERIA ISOLATED FROM Pennisetum clandestinum ASSOCIATE TO LIVESTOCK SYSTEMS IN THE ANDEAN AREA

The grass Pennisetum clandestinum is the base of the dairy systems in high mountain regions in Colombia. Due to its fertilization requirements it is vital to find sustainable alternatives for its management. In this study, four native strains of the genera Azotobacter, Pseudomonas, Micrococcus and Bacillus, isolated from P. clandestinum were used. Characterization of growth promotion ability in vitro such as phosphorus solubilization, production of indole compounds and siderophores synthesis was made for all strains, followed by a test under greenhouse conditions using 50% tricalcium phosphate plus each bacterium. After two months the bacteria,s potential to increment height, radical length, leaf and root weight in P. clandestinum was measured. The results indicated that the four strains have the ability for plant growth promotion. The treatment with the strain Azotobacter beijerinckii KA206 + 50% tricalcium phosphate increased significantly (p≤ 0.05) the assessed agronomical variables. These results surpassed the treatment with a 50% phosphate fertilization in terms of plant performance regarding roots length and dry weight. The four strains exhibited results that were significantly different (p≤ 0.05). These preliminary results suggest the existence of a feasible alternative that could reduce the phosphate fertilization with sources of low solubilization for the dairy production in sustainable agriculture systems