AbstractTwo experiments were run on coffee in a Los Guineos clay near Jayuya. The Columnaris and Puerto Rico cultivars were differentially treated with levels of major nutrients and lime to observe the results in yield and leaf-nutrient levels. No differences in yield were obtained with the Columnaris, but significant differences were obtained with the Puerto Rico cultivar The omission of nitrogen or potassium and all major nutrients together, (check) reduced the yields. Lime did not affect the yield in the presence of all the major nutrients. The overall effect of three major nutrients, as judged by regression analysis of the yield curve against level of nutrients applied fitting a second-degree equation, was not significant. Leaf samples gathered during three different periods did not show too much variation in nitrogen and phosphorus. Potassium showed a definite trend to increase with increased levels of the nutrient when applied to the soil and to vary with the time of sampling. The transformed data using Capó's equation Y = A + B arc-tan X in which X was the percentage of leaf nutrient proved to be significantly correlated with yield only with leaf potassium of samples taken in October and the yield of the incoming crop.
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