Solos e Nutrição de Plantas
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/175
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Item Production and agronomic evaluation of biogenic phosphate and potassium fertilizers(Universidade Federal de Viçosa, 2021-04-28) Matias, Patrícia Cardoso; Mattiello, Edson Marcio; http://lattes.cnpq.br/2434911980038143Solubilization of rocks using sulfuric acid produced by oxidizing bacteria from elemental S is an attractive alternative for the production of phosphate and potassium fertilizers. This process can be used with low and high solubility rocks, as it is simple, efficient, of low cost and environmentally friendly. The present study aimed to evaluate the production of biogenic acid by Acidithiobacillus thiooxidans. Chemical solubilization of phosphate rocks from Morocco (M-PR) and Serra Salitre (SS-PR) phosphate rocks, and of K silicate minerals verdete (Ve) and phonolite (Fo) rocks using commercial or biogenic sulfuric acid was evaluated and compared with the rocks in natura. Chemical, mineralogical and morphological changes were evaluated in the biogenic fertilizers produced using biogenic acid. Agronomic performance of the Morocco and Serra Salitre biogenic P-fertilizers, and verdete and phonolite biogenic K- fertilizers was also assessed in a successive corn-soybean-millet cultivation. The acidification of the rocks with sulfuric acid increased the content of extractable P and K forms in water and in 2% citric acid as well as of P in ammonium acid citrate pH 3, in relation to their in natura forms. In addition, biogenic sulfuric acid caused equal or higher solubilization P or K than commercial acid when used at a 1:5 rock:acid ratio. A reduction in intensity and/or disappearance of some phases of P or K in the X-ray diffraction, infrared and Raman spectra of biogenic fertilizers was observed with respect to those of rocks without acidulation. Dry matter yield mass as well as absorbed and accumulated P or K during corn-soybean-millet cultivation varied according to the fertilizer source. In fact, biogenic fertilizers provided more P or K to the crops than the rocks in natura; they also provided S in soluble and elemental forms. Within each P or K source, acidulation of SS-PR and Ve resulted in notorious increases in the variables under study. Keywords: Biogenic acid. Fertilizers. Phosphate rock. Potassium silicates.Item Biosolubilization of K-silicates in pelitic rock by Acidithiobacillus thiooxidans(Universidade Federal de Viçosa, 2017-02-14) Matias, Patrícia Cardoso; Mattiello, Edson Marcio; http://lattes.cnpq.br/2434911980038143Bacteria that oxidize reduced forms of S are used in industry to leach metals, such as gold and copper. The generation of acidity, from the oxidative dissolution of S, is the main mechanism by which it is possible to solubilize minerals using the bacterium Acidithiobacillus thiooxidans. In this study, the solubilization of a potassium silicate rock, regionally known as Verdete rock (VR), was evaluated by means of a biological assay using A. thiooxidans. Erlenmeyer flasks containing 9 K medium, bacterial culture and VR were incubated at 30 °C at times ranging from 0 to 49 d. After the incubation times, the filtrate and solid phase were collected. The solid phases were subjected to X-Ray Diffraction (XRD) analysis for mineralogical characterization. In the filtered, pH, redox potential and soluble contents of some elements (K, Al, Fe, Si and S) were measured. In the presence of A. thiooxidans the estimated initial pH of 4.2 was reduced to 0.57 at 49 d after incubation (dai). Under acidic conditions, with the presence of the bacterium, there was partial solubilization of the VR, evidenced by a significant increase in the concentrations of the structural elements of rock minerals. The released amounts of K, Al, Fe and Si, at 49 d, in the culture medium corresponded to 6.6, 5.8, 14.1 and 1.7 % of their total contents in VR. Mineralogical analysis showed similar changes in DRX spectra for VR samples in absence and presence of A. thiooxidans at 49 dai. In addition, the study confirmed that the solubilization of VR, as indicated by leaching of rock elements (K, Al, Fe and Si), is due to the acidification of the medium promoted by the biological catalysis of A. thiooxidans in the oxidation of S 0 , and suggests the potential use of this bacterium to solubilize silicate rocks rich in K, or other metals of interest, since it is a technology of low energy consumption compared to conventional processes. Further studies should be carried out into optimize the biosolubilization of K-silicate minerals, including the using of more sophisticated bioreactors, processes for recovering soluble elements and microbial associations.