Corn fertilization based on soil testing – An economic evaluation

Abstract

In ten field trials with corn plants in a randomised block design, in different sites in the States of Rio de Janeiro and Espírito Santo, four levels (0, 1/2, 1 and twice) of 40-80-20 kg NPK/ha indicated according to chemical and granulometric analysis of the tested soils, were studied. The formula 40-80-0 was used in two other sites of the State of Rio de Janeiro. The results, under an economic point of view showed that: a) in two sites, although there was a yield increase with fertilizer application, the gain obtained did not cover the amount expended with fertilizers; b) in five sites, for each fertilizer recommended level, there was a yield increase, from 1,075 to 1,550 kg/ha which in profit represented percentage of 11 to 60% over the applied capital, in a period of seven months; c) in other two sites, representative equations of the relation production: insume, indicated that the maximum yield increase at economic levels of fertilization ware obtained when yield of 4,922 and 9,853 kg/ha, were attained, and d) in one site, there was no significant difference among treatments.