Agriculture is characterized by the high use of fertilizers to promote higher income expectations and, due to the representativeness of this input, the cost of agricultural production is strongly affected. The present study aims to evaluate the economic efficiency of the association of olivine melilitite powder with beneficial microorganisms and the reduction of 25% chemical fertilization in maize cultivation. Five treatments were tested under a randomized block design with four replicates, represented by the application of the remineralizer associated with inoculation of bacteria of the genera Bacillus spp. and Azospirillum spp. with a 25% reduction in the recommended basal fertilization, plus fertilization with only formulated fertilizer as control treatment. The economic technical coefficients were evaluated: Gross Revenue (GR), Operating Profit (OP), Total Operating Cost (TOC), Leveling Point (LP), Profitability Index (PI) and Yield (YLD). Application of remineralizer associated with inoculation of bacterial strains of the genera Bacillus spp. and Azospirillum spp. showed the best economic indicators, promoting increments of up to 7% in PI and 15% in OP, and grain yield remained at high levels. However, application of remineralizer without inoculation of microorganisms negatively impacted grain yield, reducing PI, OP and GR. Pearson’s coefficients indicate a strong relationship of the YLD variable with PI and OP, enabling the application of olivine melilitite powder as an alternative source of nutrients in the cultivation of off-season maize. It is concluded that the application of olivine melilitite powder is economically viable and increases the profitability index, while keeping maize yield at high levels when associated with inoculation of bacteria of the genera Bacillus spp. and Azospirillum spp.

O objetivo deste estudo foi comparar metodologias de extração sequencial e digestão úmida na quantificação dos níveis de Cu, Zn, Fe e Mn em chás de Camellia sinensis. Os resultados estatísticos mostram que o método de extração sequencial foi mais sensível na quantificação dos elementos, com teores de Cu na faixa de 13.65 a 28.73 mg kg-1, Zn entre 18.89 e 54.20 mg kg-1, Fe entre 239.0 e 1403.24 mg kg-1 e Mn entre 857.25 e 1402.98 mg kg-1.  Na Análise de Componentes Principais (PCA), Cu e Zn aparecem relacionados ao chá vermelho, o Fe aparece relacionado ao chá verde enquanto o Mn oscila nos modelos, provavelmente afetado devido a particularidades dos métodos de extração. Não há na legislação brasileira limites máximos definidos para Cu, Zn, Fe e Mn em chás, mas os resultados obtidos podem ser comparados a estudos na literatura. O método de extração sequencial é mais sensível na determinação dos teores de Cu, Zn, Fe e Mn em chás de Camellia sinensis, sendo a quantificação do Mn afetada pelas metodologias nos chás branco e verde.