Using the von Bertalanffy Model to Describe Ammonia Volatilization from Conventional and Stabilized Nitrogen Fertilizers in Coffee Crop System

Abstract

ABSTRACT It has been increasingly important to control N-fertilizers, seeking high efficiency. This study aims to describe, using the von Bertalanffy model, the cumulative losses of nitrogen (N) by ammonia volatilization (NH3-N) from conventional and stabilized N-fertilizers applied in coffee orchard. The experiment was performed in Lavras municipality, Minas Gerais state, Brazil during the 2015/2016 coffee growing season. A randomized block design was used, with seven treatments (stabilized and conventional N-fertilizers) and three fertilizer applications. The evaluated stabilized and conventional N-fertilizers were: 1) prilled urea; 2) ammonium sulfate; 3) urea dissolved in water; 4) ammonium nitrate 5) urea + Cu + B; 6) urea + anionic polymer and; 7) urea + NBPT. Volatilization losses were evaluated, and the highest percentage of NH3-N losses occurred with prilled urea and urea + anionic polymer, with losses greater than 30% of N-applied depending on the number of installments. However, in the 2nd nitrogen fertilization, the von Bertalanffy model did not reach convergence for these treatments, which may have been influenced by the rainfall volume in the period. The lowest NH3-N losses were found for ammonium nitrate and ammonium sulfate, with losses that did not exceed 0.6%. The parameters were all significant and had biological interpretation, and the results will contribute to the development of more efficient fertilizers technologies for farmers. The von Bertalanffy model was adequate to describe the cumulative loss of N by volatilization of ammonia from conventional and stabilized N-fertilizers for coffee crop areas.