Material Selection for Soil Remineralization: Mineralogical, Agronomic and Environmental Perspectives on Crushed Rock Wastes

The increasing interest in the use of crushed rock wastes as soil remineralizers has created a need for a more rigorous evaluation of these materials. This evaluation should go beyond total nutrient content and consider the factors that may determine their performance under agricultural conditions. Therefore, this review aims to analyze these wastes from an integrated perspective, considering their potential for nutrient supply, their possible agronomic responses, and their environmental and operational feasibility. The literature was selected using different research platforms, prioritizing recent scientific studies directly related to the scope of the review. The selected studies indicate that high nutrient contents in rocks do not necessarily guarantee their availability, while mineralogy, pH, water availability, temperature, and microbial activity are among the factors that determine the rate and duration of nutrient release. These differences are also reflected in crop responses, which vary according to the type of rock material, soil conditions, application rate, and crop species. While some studies report improvements in soil fertility and crop yield, others show changes in soil chemical properties and evidence of mineral weathering without corresponding increases in productivity. At the same time, strategies used to increase material reactivity, such as reducing particle size, may lead to greater energy demand and potentially higher CO2 emissions associated with grinding. Another important aspect is that materials with favorable nutrient composition may have their agricultural use limited by the presence and mobility of potentially toxic elements. Based on these findings, this review organizes the selection of crushed rock wastes through a critical assessment of their reactivity and compatibility, while also considering environmental safety and conditions that may determine their agricultural feasibility.