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Your search keyword '"Gelton G. F. Guimarães"' showing total 2 results
Start Over Author "Gelton G. F. Guimarães" Journal scientific reports
2 results on '"Gelton G. F. Guimarães"'

1. Different Zn loading in Urea–Formaldehyde influences the N controlled release by structure modification

Author

Amanda S. Giroto, Stella F. do Valle, Gelton G. F. Guimarães, Nicolai D. Jablonowski, Caue Ribeiro, and Luiz Henrique C. Mattoso

Subjects
Medicine, Science
Abstract

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.

Published
2021
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2. Role of Slow-Release Nanocomposite Fertilizers on Nitrogen and Phosphate Availability in Soil

Author

Gelton G. F. Guimarães, Amanda S. Giroto, Caue Ribeiro, and Milene Mitsuyuki Foschini

Subjects
Multidisciplinary, Phosphorus, chemistry.chemical_element, 04 agricultural and veterinary sciences, 02 engineering and technology, engineering.material, 021001 nanoscience & nanotechnology, Dispersion (geology), Phosphate, Controlled release, Nitrogen, Article, chemistry.chemical_compound, Agronomy, chemistry, Chemical engineering, stomatognathic system, 040103 agronomy & agriculture, Urea, engineering, 0401 agriculture, forestry, and fisheries, Fertilizer, 0210 nano-technology, Citric acid
Abstract

Developing efficient crop fertilization practices has become more and more important due to the ever-increasing global demand for food production. One approach to improving the efficiency of phosphate and urea fertilization is to improve their interaction through nanocomposites that are able to control the release of urea and P in the soil. Nanocomposites were produced from urea (Ur) or extruded thermoplastic starch/urea (TPSUr) blends as a matrix in which hydroxyapatite particles (Hap) were dispersed at ratios 50% and 20% Hap. Release tests and two incubation experiments were conducted in order to evaluate the role played by nanocomposites in controlling the availability of nitrogen and phosphate in the soil. Tests revealed an interaction between the fertilizer components and the morphological changes in the nanocomposites. TPSUr nanocomposites provided a controlled release of urea and increased the release of phosphorus from Hap in citric acid solution. The TPSUr nanocomposites also had lower NH3 volatilization compared to a control. The interaction resulting from dispersion of Hap within a urea matrix reduced the phosphorus adsorption and provided higher sustained P availability after 4 weeks of incubation in the soil.

Published
2017
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