Análise economica sobre adubacao com sulfato de zinco via foliar na producao do cafeeiro (Coffea arabica L.)

This work was carried out with the objetive of studying the economic effect of zinc sulphate applied on the leaves of coffee plant (Coffea arabica L. cv. Bourbon Vermelho). Data were collected from the experiment on Distrofic Red Latossol (Orthox) carried out in the "municipio" of Nepomuceno, Minas Gerais, from 1974 to 1976. The experimental design was randomized blocks, split-plot on time, with eleven treatments and two replications. The amount of zinc sulphate (ZnSO47H2O - 22 per cent Zn) ranged from 0,0 to 18,0 grams/plant/year. Foliar spray was in October for the treatment 1,0 and 2,0 and splitted in October and March for the other treatments. Quadratic, cubic, transcendental and Mitscherlich production functions were tested. Statistical results showed that cubic function was the one best fitted for coffee plant yield. By using the average moying method, price stability was set from January 1981 to December 1986. The zinc sulphate rate was found to vary from 5,44 to 5,46 grams/plant/year and divided into parts in the months of October and December. A one gram reduction to the economic dosis will not occur until the price is 30 times higher than the processed coffee price, what will hardly occur since the price of fertilized was found to be lower than that fo coffee kilogram