Nitrogen fertilization effect on chemical composition and contamination by fungal-fumonisin of maize kernels

Abstract

Due to rising domestic and global market demands, studies have been performed to obtain safe raw material with high nutritional quality. Therefore, the purpose of this study was to evaluate the effect of nitrogen (N) applied in topdressing (0, 80, 160 and 240 kg.ha-1) in two key categories: 1) chemical composition (moisture, protein, lipid, ash, digestible starch, and total carbohydrates) and 2) fungi-fumonisin contamination, in maize kernels located in different areas of the cob (apex, middle and base). Field trials were conducted in the Southern Region of Brazil (Mauá da Serra, Paraná State), 2007-08 crop season, using randomized block design, with four replications. Analysis of variance (ANOVA) and an a priori significance level was set to determine significant differences using Tukey test’s (p?0.05). Incremental doses of nitrogen prompted significant changes in the chemical composition of the kernel, by increasing moisture, protein, lipid, and ash levels, while reducing digestible starch and total carbohydrate content (p<0.05). The deficiency of nitrogen (0 kg.ha-1) led to higher infections of Fusarium sp., Penicillium sp., and yeasts, and contamination by fumonisins (FB1 and FB2) in the kernel (p<0.05). Kernels from the middle of cob presented better quality with lower infection by Fusarium sp. and yeast, as reduced contamination by fumonisins (FB1 and FB2; p<0.05).