Production and agronomic evaluation of biogenic phosphate and potassium fertilizers

• Ano de defesa: 2021
• Autor(a) principal: Matias, Patrícia Cardoso
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Solos e Nutrição de Plantas
• Palavras-chave em Português: Fertilizantes fosfatados; Fertilizantes potássicos; Rochas - Solubilidade; Ciência do Solo
• Link de acesso: https://locus.ufv.br//handle/123456789/30967

Solubilization 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.