Avalia??o nutricional, produ??o e incidência do mal-do-panamá em bananeira 'Prata-An?' (AAB) adubada com K, no quarto ciclo

摘要

The objective of the present study were to estimate the rates of K to obtain the maximum physical and economic efficiency, determine the critical level of leaf K and to relate the nutritional balance of banana 'Prata An?' with the incidence of plants with Panama disease in the 4th cycle. The experiment was conducted in an oxisol, medium texture, in the semi-arid region in the northern of the State of Minas Gerais, Brazil. The treatments consisted of four rates of K (0, 400, 800 and 1200 kg ha-1 yr-1 of K2O.) These were distributed in randomized blocks with five replications. Fertilization with K increased the production of banana in the 4th cycle. The maximum physical efficiency (31.0 Mg ha-1) and economic (30.5 Mg ha-1) were obtained with the application of 969 and 707 kg ha-1 yr-1 of K2O, respectively. The critical levels of leaf K obtained were 29.5 and 27.1g kg-1 for the maximum physical efficiency and economic, respectively. The increase in rates of K provided a better nutritional balance in the banana and reduced the percentage of plants infested with Panama disease.