Produ??o de biomassa de aveia preta inoculada por Azospirillum brasiliense

Associative diazotrophic bacteria of the genus Azospirillum can promote the biological fixation of nitrogen and act as a biostimulant for plant growth through the production of phytohormones, such as auxins, cytokinins and gibberilins. The objective of this work was to evaluate the nutritive and nutrient absorption characteristics of black oats (Avena strigosa) submitted to nitrogen doses and inoculation of seeds by Azospirillum brasilense, in the first cultivation in alumino-ferric Red Latossol. The experimental design was a randomized complete block design with four replications and the arrangement of the treatments in a factorial scheme (doses, with or without inoculation by Azospirillum brasilense). The results were submitted to analysis of variance, discriminating the means by Tukey (qualitative variable). The variables evaluated in the three cuts were: shoot dry weight, plant height, nitrogen and phosphorus content in shoot, nitrogen and phosphorus extraction. The production of shoot dry mass, plant height, nitrogen content, nitrogen extraction and phosphorus extraction were positively influenced by the application of increasing doses of nitrogen. The phosphorus content had an opposite result, that is, it decreased as the nitrogen doses increased. The inoculation by Azospirillum brasilense provided higher phosphorus content in shoot, lower shoot dry mass and lower nitrogen extraction. The nitrogen content had a different behavior, because in some cuts and doses of nitrogen the inoculation by A. brasilense provided positive and negative results.As bact?rias diazotr?ficas associativas do g?nero Azospirillum podem promover a fixa??o biol?gica de nitrog?nio e atuar como bioestimulante para o crescimento vegetal atrav?s da produ??o de fitohorm?nios, como auxinas, citocininas e giberilinas. O objetivo do trabalho foi avaliar as caracter?sticas produtivas e de absor??o de nutrientes em aveia preta (Avena strigosa) submetida a doses de nitrog?nio e a inocula??o de sementes por Azospirillum brasilense, em primeiro cultivo em Latossolo Vermelho alumino f?rrico h?mico. O delineamento experimental foi blocos ao acaso, com quatro repeti??es e o arranjo dos tratamentos em esquema fatorial (doses, com ou sem inocula??o por Azospirillum brasilense). Os resultados foram submetidos ? an?lise de vari?ncia, discriminando as m?dias por Tukey (vari?vel qualitativa). As vari?veis avaliadas nos tr?s cortes realizados foram: massa seca da parte a?rea, altura de plantas, teor de nitrog?nio e f?sforo na parte a?rea, extra??o de nitrog?nio e f?sforo. A produ??o de massa seca da parte a?rea, altura de plantas, teor de nitrog?nio, extra??o de nitrog?nio e extra??o de f?sforo foram influenciadas positivamente pela aplica??o de doses crescentes de nitrog?nio. O teor de f?sforo apresentou resultado contr?rio, ou seja, diminuiu conforme aumentaram as doses de nitrog?nio. A inocula??o por Azospirillum brasilense proporcionou maior teor de f?sforo na parte a?rea, menor massa seca de parte a?rea e menor extra??o de nitrog?nio. O teor de nitrog?nio demonstrou comportamento diferenciado, pois em alguns cortes e doses de nitrog?nio a inocula??o por A. brasilense proporcionou resultados positivos e negativos