Abstract

MORENO, Laura Y  and  GALVIS, F. Biofertilizer potential of diazotrophic bacteria isolated from samples of rhizospheric soil. Pastos y Forrajes [online]. 2013, vol.36, n.1, pp.33-37. ISSN 0864-0394.

Plant growth promoting bacteria are capable of adapting, colonizing and persisting in the plant rhizosphere, which favors plant growth and development. In this work 32 native strains of diazotrophic bacteria were isolated, from rhizospheric soil samples of different crops, identified through traditional soil cultures and the BBL CRYSTAL system. The biochemical identification was made through polymerase chain reaction (PCR). Nine isolates were determined as Stenotrophomonas maltophilia and one as Azotobacter vinelandii, of which three coincided in the biochemical and molecular identification. A greenhouse trial was conducted to evaluate the fertilizer effect on corn plants, according to a randomized block design and nine treatments, in triplicate: treatment 1: A. vinelandii ATCC 9046; treatments from 2 to 7 for the six isolates; treatment 8 for chemical fertilization; and treatment 9 for soil without fertilization (control). The isolates M8-10, M10-1 and M11-3, identified as S. maltophilia by PCR, had better results in plant emergence, stem diameter and leaf and stem length. Finally, M10-1 was determined to show plant emergence and growth values higher than the mean and upper limit, as compared with the other isolates and controls, which makes it a potential biofertilizer.

Keywords : bacterium; nitrogen fixation.

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