Quality of the coffee grains in function of doses potassium

Abstract

Two field experiments were conducted, located on a Rhodic Acrudox in São Sebastião do Paraíso and other on a Xanthic Acrustox in Patrocínio, in Minas Gerais state, Brazil. The objective this research was to define potassium rates for maximum yield and quality of the coffee grains, Coffea arábica L. (Rubiaceae), as well as the place of better response to the fertilization with potassium doses. In both places, the coffee cultivar used was Catuaí Vermelho, aged six years old, planted in spacing 3.5 m between rows and 0.7 m between plants in the rows. Four fertilizing doses of K₂O were applied, corresponding to 0, 120, 240 and 480 kg . ha^-1, as KCl. The experimental design used was the randomized block complete, with four replications. The yield, enzyme activity of poliphenyloxidase, coloration index, total tirable acidity and total sugars of coffee grains were determined over four annual harvests for each place. The quality improved with potassium fertilizing doses and the better doses of K₂O was 266 kg . ha^-1 for a maximum yield of 46,4 sacks . ha^-1 for potassium level in the soil between 60 to 70 mg . dm^-3. The quality of Patrocínio’s coffee was better than of São Sebastião do Paraíso for the same dose of potassium fertilizing