Differential Response of Corn and Sweet Potatoes to Zn Applications in an Oxisol in Northwestern Puerto Rico

Abstract

Experiments were conducted in an Oxisol in an attempt to clarify the role of Zn in crop production. The Capo fertilizer-yield equation was applied to the first of two consecutive corn crops of Pioneer X-3068 and Funk's G-795W, grown in an exposed Coto clay subsoil. The equation made possible the estimation of grain corn yields with a fair degree of precision. A crop of a white-fleshed sweet potato cultivar (Mina) was grown in a typical undisturbed Coto clay near the site where the corn experiments were conducted. Near maximum yields could be obtained with the application of only 3.3 kg/ha of Zn. Stover yields were estimated with a very high degree of precision (r² = 0.98) from the corresponding equation. No response to Zn was obtained in the second consecutive corn crop (Funk's G-795W) nor in the sweet potato crop.