Amanda S Giroto1, Stella F do Valle1,2, Gelton G F Guimarães3, Nicolai D Jablonowski4, Caue Ribeiro5, Luiz Henrique C Mattoso1. 1. National Nanotechnology Laboratory for Agribusiness (LNNA), Embrapa Instrumentação, XV Novembro Street, CP: 741, São Carlos, SP, 13560-206, Brazil. 2. Department of Chemistry, Federal University of São Carlos, Washington Luiz Highway, km 235, São Carlos, SP, 13565-905, Brazil. 3. Agricultural Research and Rural Extension Company of Santa Catarina, 6800 Highway, Antônio Heil, Itajaí, Santa Catarina, 88318112, Brazil. 4. Forschungszentrum Jülich GmbH, Institute of Bio- and Geosciences, IBG-2: Plant Science, 52425, Jülich, Germany. n.d.jablonowski@fz-juelich.de. 5. National Nanotechnology Laboratory for Agribusiness (LNNA), Embrapa Instrumentação, XV Novembro Street, CP: 741, São Carlos, SP, 13560-206, Brazil. caue.ribeiro@embrapa.br.
Abstract
Nitrogen fertilization has been a critical factor for high crop productivity, where urea is currently the most used N source due to its high concentration and affordability. Nevertheless, urea fast solubilization leads to frequent losses and lower agronomic efficiency. The modification of urea structure by condensation with formaldehyde has been proposed to improve nutrient uptake by plants and to reduce environmental losses. Herein we show that the co-formulation with Zn strongly modifies the N release (in lab conditions) and, more important, the Zn source-ZnSO4 or ZnO-has a critical role. Urea-formaldehyde (UF) served as a matrix for the zinc sources, and chemical characterizations revealed that Zn particles influenced the length of the polymeric chain formation. Release tests in an aqueous medium showed that the UF matrix favors ZnO release and, on the other hand, delays ZnSO4 delivery. Soil incubation with the fertilizer composites proved the slow-release of N from UF, is ideal for optimizing nutritional efficiency. Our results indicated that the ZnO-UF system has beneficial effects for both nutrients, i.e., reduces N volatilization and increases Zn release.
Nitrogen fertilization has been a critical factor for high crop productivity, where n class="Chemical">urea is currently the most used N source due to its high concentration and affordability. Nevertheless, urea fast solubilization leads to frequent losses and lower agronomic efficiency. The modification of urea structure by condensation with formaldehyde has been proposed to improve nutrient uptake by plants and to reduce environmental losses. Herein we show that the co-formulation with Zn strongly modifies the N release (in lab conditions) and, more important, the Zn source-ZnSO4 or ZnO-has a critical role. Urea-formaldehyde (UF) served as a matrix for the zinc sources, and chemical characterizations revealed that Zn particles influenced the length of the polymeric chain formation. Release tests in an aqueous medium showed that the UF matrix favors ZnO release and, on the other hand, delays ZnSO4 delivery. Soil incubation with the fertilizer composites proved the slow-release of N from UF, is ideal for optimizing nutritional efficiency. Our results indicated that the ZnO-UF system has beneficial effects for both nutrients, i.e., reduces N volatilization and increases Zn release.