Bactéria fixadora de nitrogênio e produtividade de arroz irrigado por inundação

Abstract

The objective of this work was evaluate the effect of bacteria fixative of nitrogen Azospirillum brasilense in flooded irrigated rice yield. The experiment was performed in an agricultural nursery covered with screen, in an Alfisol. They were used flooded irrigated rice cultivars INIA Olimar, Puitá Inta-CL, Br Irga 409 e Irga 424, establish 4 experiments in delineament completely randomized, in factorial scheme 5 x 4, with 4 replications. The treatments were 5 rates of nitrogen (0, 40, 80, 120 e 160 kg ha-¹ de N), and 4 rates of liquid inoculant with bacteria Azospirillum brasilense strains Ab-V5 and Ab-V6 (0, 1, 2 and 4 times to recommendation). In second set of experiments, with rice cultivars Puitá Inta-CL e Br Irga 409, it was used a factorial scheme 4 x 2. Four rates of A. brasilense strains Ab-V5 and Ab-V6 (0, 1, 2 and 4 times to recommendation of 100 mL ha-¹ ) and whit and without rice seed treatment with insecticide and fungicide. It was evaluated dry mass of aerial part, number of panicles and rice grain yield pot-¹ . The flooded irrigated rice seed inoculation, cultivars INIA Olimar, Puitá Inta-CL, Br Irga 409 e Irga 424, with A. brasilense did not increase rice grains yield. The nitrogen application increased the grains yield of four flooded irrigated rice cultivars up to the level of 160 kg ha-¹.