Abstract

The corn crop is one of the most cultivated in the world and one of the most need studies that seek alternatives on the use of Azospirillum brasilense. This bacterium produces growth hormones that may benefit the corn crop. The work objective was to verify the agronomical performance of corn crop, in function of foliar Azospirillum brasilense inoculation, associated with nitrogen doses. The research was performed in Selvíria, Mato Grosso do Sul State, Brazil, which is in the Brazilian Cerrado. The corn crop was cultivated during season (Spring/Summer) and late season (Summer/Autumn), under conventional tillage system. Experimental design of randomized blocks was used, with factorial scheme 4 × 2. The treatments were made in four nitrogen doses (0, 30, 60 and 90 Kg ha^-1) with and without the foliar applying (in stage V6) of the inoculant containing A. brasilense. The inoculant used had the strains AbV₅ and AbV₆ of A. brasilense (2×10⁸ viable cells mL^-1) and, the dose 200 mL ha^-1 was used. The nitrogen fertilization was made with ammonium sulfate, also on phenological stage V6. The following evaluations were made: Final plant population, foliar nitrogen content, foliar chlorophyll index, ear insertion height, plants height, stalk diameter, ears length, ears diameter, thousand grain weight and grain productivity. The foliar inoculation with the A. brasilense bacterium proved to be advantageous for the corn crop, and therefore, an option for the farmer. Because of the large volume of products used in seed (fungicide, insecticide, plant growth regulators) and the lack of information on the degree of interference of these products on the bacteria, it becomes pertinent the study of other inoculation forms on crops. Other studies that verify the influence of A. brasilense bacteria in foliar application on the physiology of the shoot and root of crops should be encouraged.

Key words:  Zea mays L., inoculation, nitrogen, diazotrophic bacteria.

Abbreviation

CEC, Cation Exchange Capacity; BS, Base Saturation