Resumo

GARRIDO, María F; CARDENAS, Diana M; BONILLA, Ruth R  e  BALDANI, Vera L. Effect of the edaphoclimatic factors and pasture species on the diversity of diazotrophic bacteria. Pastos y Forrajes [online]. 2010, vol.33, n.4, pp. 1-1. ISSN 0864-0394.

In order to study the diversity of diazotrophic bacteria associated to soils and cultivated pastures in the Cesar Valley and Savanna microregions, the recounts of the bacteria genera (Azospirillum, Herbaspirillum, Burkholderia, Gluconacetobacter, Derxia, Beijerinckia and Azotobacter) associated to three grasses (Panicum maximum, Dichanthium aristatum and Brachiaria sp.) were made in two seasons (rainy and dry season). The recount was made from samples of rhizospheric soil, roots and leaves in solid (LG, LGD and BEIJERINCKIA) and semisolid specific culture media (NFb, LGI, JNFb, JMV, LGI-P), using a divided plot design with a 3 (pasture species) x 3 (strata) x 2 (seasons) factorial arrangement. The results showed that the drought condition influenced the number of diazotrophic bacteria present in the three grasses used in cattle feeding in the Cesar Valley and Savanna, Colombia. In the dry season a decrease was observed in the number of bacteria in the root and soil.

Palavras-chave : Brachiaria sp; diazotrophic bacteria; Dichanthium aristatum; nitrogen fixation; Panicum maximu.

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