Diversidade de bactérias fixadoras de nitrogênio presentes em solos e plantas de Brachiaria brizantha cv. Marandu cultivadas em sistemas integrados

Abstract

Brazilian cattle ranching is one of the most productive in the world contributing to the country's economy in recent years. The sector currently concentrates on large properties that are focused on meat production, since this product is the most valued and export-oriented. Livestock is divided into two types, intensive livestock, which consists of the cultivation of animals in confinement, and extensive, which consists of the breeding of loose animals with the grassland feeding base. The adoption of selected grasses leveraged the support capacity and also the animal development among the cultivars used have the Brachiaria brizantha cv. Marandu, which stands out for presenting qualities of interest, associated with pasture we can find the microbiological diversity near the soil and plants, where several researches in the sector are currently developed in the search for new isolates that can provide benefits in the development of plants as in the roots , improved soil nutrient uptake and biological nitrogen fixation. Thus, the objective of this research was to evaluate the amount and diversity of nitrogen fixing bacteria present in the soil and associated with Brachiaria brizantha cv. Marandu, in Sinop - Mato Grosso, Brazil. Isolations were performed on soil, rhizosphere, root, shoot and seed. The biological nitrogen fixation test was performed using semi-solid NFb culture medium. Of the 360 isolates tested 30 isolates of the root, 29 of the rhizosphere, 20 isolates of the aerial part and 14 isolates of the seed showed the capacity to fix nitrogen.