Agronomic performance of out-of-season maize crop in response of application N-fertilizer combined with biological inoculant in Mato Grosso

Abstract

The high price of nitrogen fertilizer is an aggravating factor for the corn production costs in the out season and its use may be lead environmental damages. Diazotrophic bacteria have the ability to associate with different plant species and nitrogen supply. Thus, the objective of this study was to evaluate the agronomic performance of winter maize inoculated with Azospirillum brasilense grown with nitrogen levels in the state of Mato Grosso. The experiment was carried out and scaled the field with six treatments: 42 kg N ha-1 with inoculant; 31.5 kg N ha-1 with inoculant; 21 kg N ha-1 with inoculant; 0 kg N with inoculant; 0 kg N without inoculation; 42 kg N ha-1 without inoculation. The inoculant tested contained two strains of A. brasilense. Nine variables were evaluated after harvest and the data were assessed by Kruskal-Wallis test (p ≤ 0.01) test. The variables productivity, number of rows of grains of corn, number of kernels per row, diameter spike, spike weight and weight of the cob responded positively to inoculation with 42 Kg of N. The variables mass of thousand grains, diameter of cob and weight of straw did not change according to the treatments. The productivity in the treatments with reduced N doses was equal to high N doses without inoculation. Those results showed the inoculant use associated with low N doses may be a new way to reduce the N use without decrease the corn productivity in the out season in Mato Grosso.