Innovative Use of Stone Waste for Sustainable Fertility Management in Tropical Soils

The sustainable reuse of mining and stone-processing waste is increasingly recognized as a strategy for soil remineralization and circular resource management in agriculture. However, the geochemical interactions between ornamental stone waste and highly weathered tropical soils are still insufficiently understood. This study evaluated the effects of incorporating ornamental stone waste on the chemical, physical, and mineralogical properties of a Red-Yellow Argisol rich in organic matter. A greenhouse experiment was conducted using four treatments: control soil and soil amended with 5%, 10%, and 15% stone waste. The incorporation of stone waste significantly improved soil chemical properties, increasing pH from 4.3 (control) to 5.6, 6.3, and 6.9 in the 5%, 10%, and 15% treatments, respectively. Base saturation increased from 48% in the control soil to values above 90% in all amended treatments, while exchangeable acidity was substantially reduced. Calcium concentrations increased from 4.5 to 13.1 cmolc dm^-3 and magnesium from 1.0 to 3.1 cmolc dm^-3, indicating enhanced nutrient availability. Mineralogical analyses identified quartz, dolomite, feldspar, and enstatite as dominant phases, and their incorporation increased the relative abundance of silicates and carbonates in the soil. Fourier-transform infrared spectroscopy indicated the formation of organo-mineral associations, suggesting enhanced stabilization of soil organic matter. In terms of physical properties, bulk density increased from 0.73 to 0.93-1.03 g cm^-3, while macroporosity decreased from 18% to 8-12%, and microporosity increased up to 35% depending on the treatment. These changes reflect structural modifications associated with the addition of fine mineral particles. Overall, the results demonstrate that ornamental stone waste acts as an effective soil remineralizer, improving soil fertility and altering structural properties, while providing a sustainable alternative for the reuse of mining byproducts in tropical agricultural systems.