Aislamiento de bacterias fijadoras de nitrógeno y bioestimuladoras del crecimiento vegetal con potencial en la producción de biofertilizantes

Abstract

The isolation and identification of nitrogen fixing microorganisms with potential for the development of biofertilizers or substances that stimulate plant growth is a vital component for agricultural production, since conventional agriculture has been based on the excessive use of inorganic fertilizers. Therefore, an alternative to these problems is the use of biological methods, among them the selection of bacterial strains with these characteristics. The present research work was carried out with the objective of obtaining nitrofijadoras bacterial strains and stimulators of plant growth to contribute with the establishment of the germplasm bank with potential in the production of biofertilizers. The sampling was carried out in areas of the Faculty of Agricultural Sciences of the Technical University of Ambato in the amaranth, blackberry, carrot and mashua cultivation of the root and rhizospheric soil, where 26 isolates were obtained in a selective medium Ashby mannitol, for the identification, morphological, physiological and biochemical tests were performed, in which the strains AUTA AR2, AUTA AS5, MUTA AR4, MUTA AR5, MUTA AS6, SHUTA AR2, SHUTA AS3 and SHUTA AS4 resemble the genus Azotobacter. According to the capacity to produce ammonium, in the amaranth culture the strains with greater capacity were AUTA AR6, AUTA AR3, AUTA AS1, AUTA AS4 and AUTA AS6, in arrears MUTA AR4, MUTA AR5, MUTA AR1, MUTA AR2 AND MUTA AR3, carrot ZUTA AS1.1, ZUTA AS3, ZUTA AS1 and ZUTA AS2 and in mashua SHUTA AS1, SHUTA AS3, SHUTA AS4, SHUTA AS5 and SHUTA AR2. According to the nitro fijadora capacity and the tests carried out, 15 bacterial strains were selected to test the efficiency in the nursery. It was obtained as results that the strains AUTA AR6 and MUTA AR4 were the best in height of stem and number of leaves in comparison to the control treatment. Based on the results, these two treatments could be used for the preparation of biopreparations, however it is necessary to carry out more studies such as molecular biology for its identification.