Abstract
Data are reported here from a 4-year field experiment in an Alonso clay with old coffee trees in the vicinity of Adjuntas and Lares, in the heart of the Coffee Region of Puerto Rico. The experiment included super- and hyperphosphate applied either with or without lime, and at rates of 0, 50, 125, and 200 pounds to the acre. Lime was applied at a rate of 4 tons to the acre. No significant differences were measured in coffee yields which could be attributed to any of the treatments. These results are analyzed in the fight of previous similar work. The general statement could be made that lime applications to acid Alonso clay soils do not affect the yields of coffee in any way, except perhaps when the acidity is high (pH 4.0 to 4.5), in which case applications of 1 ton are apparently sufficient. There is no need to apply phosphatic fertilizers to Alonso soils. However, the beneficial effects of these fertilizers have been demonstrated when dealing with other soils.
