RAFAEL CADORE
Abstract:
Azospirillu bacteria genus are atmospheric nitrogen (N) fixators are considered plant growth promoters in non-leguminous plants. The use of inoculants containing these bacteria mainly in corn crop in an attempt to reduce the use of nitrogen fertilizers, improve plant growth and development and increase grain yield is a good alternative for sustainable agriculture, but several factors may interfere in obtaining these benefits, such as the used hybrid, edaphoclimatic conditions and the adopted management. Thus, the objective was to evaluate the effect of inoculation with Azospirillum brasilense associated with nitrogen fertilization on maize hybrids recommended for southwestern Goiás by two experiments. In the first field experiment in the second crop with ten hybrids submitted to Azospirillum brazilense inoculation and nitrogen rates in coverage consisting of the treatments: no inoculation and no topdressing, no topdressing and inoculation, 35 kg ha-1 of N in cover and inoculation, and 70 kg ha-1 of N in cover and inoculation thus forming a 10 x 4 factorial arrangement. The variables related to growth and development, analysis of nitrate reductase enzyme activity and yield variables and their effects were evaluated components in which it was concluded that the inoculation itself was not able to generate significant increases in the analyzed variables, but with the application of nitrogen fertilization in coverage it was possible to detect the positive effect of the doses tested in some variables, thus under the conditions under study The most productive hybrids were BioGene 7046®, Dekalb 310® and Agroeste 1596®. The second field trial in the first crop aimed to evaluate application methods of Azospirillum brasilense (no application, seed application, foliar application and the combination of seed and foliar application) associated with nitrogen rates (0, 35 and 70 kg ha-1 of N) in two hybrids that had higher amplitude in (0, 35 and 70 kg ha of N) in two hybrids that had greater amplitude in grain yield in the previous experiment (BioGene 7046® and Dekalb 310®) . The variables related to growth and development, analysis of nitrate reductase enzyme activity and yield variables and their components were evaluated. Inoculation with Azospirillum brasilense regardless of the method of application had no effect on growth and development variables and did not increase grain yield. There was only effect of inoculation with A. brasilense in the seeds on nitrate reductase activity, specifically for one of the hybrids associated with one of the nitrogen rates in coverage. Nitrogen fertilization in mulching is an indispensable practice, providing increase in growth and development of corn plants. (0, 35 and 70 kg ha-1 of N) in two hybrids that obtained greater amplitude in grain yield in the previous experiment (BioGene 7046® and Dekalb 310®). The variables related to growth and development, analysis of nitrate reductase enzyme activity and yield variables and their components were evaluated. Inoculation with Azospirillum brasilense regardless of the method of application had no effect on growth and development variables and did not increase grain yield. There was only effect of inoculation with A. brasilense in the seeds on nitrate reductase activity, specifically for one of the hybrids associated with one of the nitrogen rates in coverage. Nitrogen fertilization in mulching is an indispensable practice, providing increase in growth and development of corn plants.
