Estudos sôbre a alimentação mineral do cafeeiro: XXI. efeito da adubação N, P, K e orgânica na composição mineral do grão e na qualidade da bebida. (2a. Nota)

Portuguese. O efeito da adubaçao NPK e da matéria orgânica na composição mineral do grão e na qualidade da bebida (prova de xícara) foi estudado. Verificou-se que a adubação fosfatada e o uso da matéria orgânica não influiram nas características mencionadas. A adubação nitrogenada e potássica aumentou o teor dos elementos correspondentes no grão e prejudicou pouco mas, significativamente a qualidade da bebida. Esses dados devem ser encarados com cautela e tidos apenas como preliminares.

English. In this second year of work, research was carried out concerning, the effect of N, P, K and organic fertilization on the mineral composition of the coffee bean and in the quality of the beverage. The material employed was obtained from a NxPxK, 2³ , factorial experiment with split plot (with and without organic matter). The test area is located in poor, deep and, sandy soil; Coffea Arabica L., Var. "Bourbon Vermelho" is the plant source. The main findings are as follows: a) N content in the bean was raised by the application of N in the soil. The use of K increases the level of K in the bean. The level of total P and soluble P was not affected by P fertilization. No treatment affected the S level in the bean. The level of the elements analysed was not affected significantly by the organic matter applied to the soil. b) Fruits collected in treatments where N and K were used gave significantly lower quality beverage. The quality of beverage wasn't affected by the organic matter. c) It was found a negative and significant (1%) correlation between N level in the bean and quality of beverage (r = -0,642). For K the correlation was found to be r - -0,449, significant at 10% of probability. No similar correlation was found with respect to P.