Bactérias promotoras de crescimento e adubação nitrogenada na produtividade e qualidade de capim mavuno

Abstract

Currently, the use of ecologically correct and environmentally viable alternatives has been increasingly sought to solve agricultural problems resulting from the excessive use of chemical products in soils and their impacts. The use of growth-promoting bacteria (GPBP) such as Pseudomonas fluorescens and Azospirillum brasilense is another feasible alternative, with lower implementation and maintenance costs for pastures. Therefore, the present study aimed to evaluate the use of GPCP bacteria on the production of forage plants, comparing the productive indexes of these forages. The aim of this study was to evaluate the effect of inoculation with growth-promoting bacteria on the productive and qualitative characteristics of campim-mavuno. The experiment was conducted in the experimental area of the State University of Goiás - São Luís de Montes Belos Campus, Goiás. The experimental design used was randomized blocks, with four replicates per treatment. Eight treatments with microorganism inoculation and nitrogen fertilization strategies were used: Control (no inoculation and no N); 100 kg ha-1 of N; Azospirillum brasilense, in the N; Pseudomonas fluorescens, in N; A. brasilense and P. fluorescens, in the N; A. brasilense, plus 50 kg ha-1 of N; P. fluorescens, plus 50 kg ha-1 of N; and A. brasilense + P. fluorescens, plus 50 kg ha-1 of N. The concentration of microorganisms present in the product was 1x108 CFU mL-1 of A. brasilense and 1x108 CFU mL-1 of P. fluorescens. Each experimental unit had 9 m², was 3 m long and 3 m wide. The quantitative characteristics evaluated were: height of the forage canopy, population density of tillers, leaf:stem ratio and dry mass production. For the qualitative characterization, a bromatological analysis was performed. The inoculation of mavuno grass, added with N, provided an increase in the population density of tillers and dry mass production, in addition to the improvement of some bromatological characteristics. The inoculation of mavuno grass, without N, is not sufficient to promote good results. The bacterium P. fluorescens + 50 kg ha-1 of N, in some situations, was superior to the treatment that was used co-inoculation with A. brasilense.