Nutrição nitrogenada e potássica afetando crescimento, produção, composição química e qualidade da bebida de Coffea arabica L.

• Ano de defesa: 2010
• Autor(a) principal: Clemente, Junia Maria
• Orientador(a): Martinez, Hermínia Emília Prieto
• Banca de defesa: Neves, Yonara Poltronieri , Santos, Ricardo Henrique Silva , Sakiyama, Ney Sussumu
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Nitrogênio; Potássio; Qualidade
• Palavras-chave em Inglês: Nitrogen; Potassium; Quality
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4524

Nitrogen and potassium are the nutrients of greatest demand for coffee. Its deficiency can cause metabolic disturbances and affect the development of coffee plants and consequently the production and physical and chemical characteristics of grains, since nutrients are involved in biosynthesis and metabolism of compounds related to chemical quality of raw coffee beans. This study evaluated the effect of nitrogen (N), potassium (K) and N:K ratio on vegetative growth, yield and physical characteristics of coffee grains, besides the effect on the main attributes related to the quality of beverage of raw coffee beans. Treatments consisted of four N:K ratio in nutrition solution, obtained by keeping constant the concentration of N and varying concentrations of K, and a control treatment with lower concentrations of N. The concentration of K used were 1.08, 2.15, 3.23 and 5.38 mmol/L combined with a dose of 6 mmol/L of N, resulting in the N:K ratio: 1.0: 0.5; 1.0:1.0, 1.0:1.5, 1.0:2.5. The control treatment was compound of doses of 3 and 1.61 mmol/L of N and K respectively, resulting in the N:K ratio 1.0:1.5. The coffee cultivar used was Catuaí Vermelho IAC 99 germinated in conventional substrate and transferred to hydroponic cultivation at the onset of the first true leaves pair. There was used a sub-irrigation system with expanded clay as substrate. Besides the cup test, there were made grain analysis of polyphenoloxidase activity (PPO), caffeine, phenolic compounds (FT), total sugar (AT), reducing sugars (ARS) and non-reducing sugars (ANR), total acidity (ATT), coloration index (IC), leaching of potassium (LK) electrical conductivity (CE) and pH. In addition, for this study analysis were performed for the variables of vegetative growth: height, number of nodes in the orthotropic branch, number of nodes in the eighth plagiotrophycal branch (Branch index), stem diameter, fruit number of the branch index, chemical analysis of leaves and grains, chlorophyll, plant production and grain classification according to size. The N:K ratio influenced the quality of the beverage evaluated by cup test. Potassium influenced all variables, except the PPO activity. The high N did not influence the production of cherry coffee and restricted quality of the beverage. The quality of the beverage was proportional to the PPO activity, caffeine, coloration index and reduced sugars and inversely proportional to the total acidity, leaching of potassium, pH and electrical conductivity. The effect of N:K ratio was observed in the following vegetative growth variables: height, number of nodes of the plagiotrophycal branches and stem diameter, however, was not important in determining the yield of individual plants and in the classification of benefit grain size. The N content in plant tissues was proportional to N in nutrition solution, however, was not accompanied by higher averages of all variables. The K affect vegetative growth until a maximum point around 5,38 mmo/L that corresponds to 3,25 dag/kg of K in the index leaves.