Inoculação de sementes com bactéria diazotrófica e aplicação de nitrogênio em cobertura e foliar em milho

Abstract

ResumoConsiderando a importância do manejo do nitrogênio e da sua fixação biológica através de bactérias diazotróficas, conduziu-se este trabalho com o objetivo de avaliar o desempenho agronômico do milho, em função da inoculação das sementes com Azospirillum brasilense e da aplicação de nitrogênio em cobertura e foliar. O experimento foi conduzido no município de Selvíria -MS, durante o ano agrícola 2010/2011, sob Latossolo Vermelho distrófico típico argiloso (20º 20' S e 51º 24' W, com altitude de 340 m). Foram estabelecidos dezesseis tratamentos com quatro repetições, em blocos ao acaso, resultantes da combinação dos fatores A. brasilense (com e sem inoculante), dose de nitrogênio (0 e 90 kg ha -1 , em V 5 ) e ureia foliar (0, 4, 8 e 12 %: aplicações em V 5 e V 8 ). O híbrido utilizado foi o DKB 390 YG ® , semeado no espaçamento de 0,9 m entre linhas. Foram mensurados componentes morfológicos e produtivos da cultura e produtividade de grãos. Houve aumento de produtividade de grãos do milho pela inoculação das sementes com A. brasilense. A aplicação de 90 kg ha -1 de nitrogênio em cobertura proporcionou maior índice de clorofila foliar, diâmetro de colmo e prolificidade, entretanto, a produtividade não foi incrementada. A aplicação de ureia foliar não apresentou eficiência agronômica e, portanto, não deve ser utilizada como única forma de fornecimento e alternativa de complementação de nitrogênio à cultura. Palavras-chave: Zea mays, Azospirillum brasilense, adubação nitrogenada, adubação foliar, produtividade AbstractConsidering the importance of nitrogen management and its biological fixation with diazotrophic bacteria, this study was carried out aiming to evaluate the agronomic performance of maize, in response to seed inoculation with Azospirillum brasilense and nitrogen application in side-dressing and leaf. The experiment was conducted in Selvíria, Mato Grosso of Sul State, Brazil, during the growing season 2010/2011, on a clayey Rhodic Haplustox (20º 20' S and 51º 24' W, with altitude of 340 m). Sixteen treatments were established with four replications, in randomized blocks with the combination of the factors A. brasilense (with and without inoculante), nitrogen rate (0 and 90 kg ha -1 , in V 5 growth stage) and urea leaf application (0, 4, 8 and 12%: application in V 5 and V 8 growth stage). The maize hybrid

Inoculation of Diazotrophic Bacteria and Nitrogen Fertilization in Topdressing in Irrigated Corn

“…However, in corn production systems, the need for fertilizers is known as one of the factors that increases the production costs (COSTA et al, 2012b); in addition, its misuse can cause environmental harm. However, it is known that inoculating corn seeds with diazotrophic bacteria can improve the crop nitrogen supply (DARTORA et al, 2013;KAPPES et al, 2013) and can thereby reduce the need for externally applied nitrogen fertilizers.…”

“…One alternative to traditional fertilization methods is inoculation of corn seeds with diazotrophic bacteria, which has been found to decrease the need for nitrogen fertilizer application (LANA et al, 2012;KAPPES et al, 2013;DARTORA et al, 2013). Boddey and Döbereiner (1995) discovered the potential of microaerobic diazotrophic bacteria, especially those of the genus Azospirillum, to fix atmospheric nitrogen in free living condition.…”

“…The increase in corn yield due to inoculation with Azospirillum in trials conducted in Brazil is correlated with an increase in the absorption of not only nitrogen but also other nutrients such as phosphorus (P) and potassium (K) (DARTORA et al, 2013;KAPPES et al, 2013). These nutrients are of great importance in tropical soils, where they are naturally scarce.…”

Technical and Economic Viability of Corn with Azospirillum brasilense Associated with Acidity Correctives and Nitrogen

“…In several studies, increases in corn grain yield are reported with the application of N doses in the cover (Kappes et al, 2013;Kappes et al, 2014;Galindo et al, 2016), einforcing the results obtained. Meira et al (2009) observed that NH 3 volatilization losses among the various fertilizers, including urea, did not reflect corn yield.…”

Inoculation with Bradyrhizobium sp. and Azospirillum brasilense Associated with Application of Cobalt and Molybdenum on Nutrition and Soybean Yield

“…Corn plants that were inoculated with A. brasilense had greater LCI than those that were not inoculated, in two crop seasons [31]. Kappes et al [32] and Quadros et al [33] found that plants inoculated with A. brasilense had improved LCI. These divergent results can be explained by the fact that A. brasilense increases reductase activity of nitrate when they grow endophytically plants [19], a fact of minor importance for soybean plant that spends more metabolic energy (ATP) to biologically fix N 2 in the root nodules in relation to nitrate reduction assimilation.…”