Dunite solubilization kinetics in silicon-magnesium fertilization

Abstract

Dunite [(MgFe)₂SiO₄] is an igneous rock that remineralizes and corrects soil acidity as well as providing magnesium (Mg²⁺) and silicon (Si⁴⁺) to several crops of agricultural interest. However, few studies have verified its solubility in tropical soils, which is important for its use in different tropical conditions. In a greenhouse incubation experiment, this study verified the solubilization kinetics of dunite in clayey, medium texture, and sandy soils. The soil samples were dried and sieved (50 mesh), placed in plastic cups (300 g), and incubated for six months (at 60%–80% of the moisture retention capacity). Samples for pH (CaCl₂ extractor), Mg²⁺ (resin extractor), and Si⁴⁺ (CaCl₂ extractor) analysis were taken at 10, 20, 30, 40, 50, 60, 70, 85, 100, 115, 130, 150, and 180 days after incubation. The application of dunite led to an increase in Mg²⁺ and Si⁴⁺ contents and an acidity correction in the three studied soils. Its controlled release presents method for increasing the efficiency of magnesium fertilization. It allows for fewer losses due to Mg²⁺ leaching, as the dissolution kinetics are slower than soluble sources and have a residual effect for subsequent crops.

Keywords:

• Agromineral
• magnesium fertilization
• remineralizer
• silicon
• stonemeal

Acknowledgments

Thanks to the National Council for Scientific and Technological Development (CNPq) for an award for ‘Excellence in Research,’ awarded to the second and fifth authors.

Disclosure statement

No potential competing interest is reported by the authors.