Carbonatites as rock fertilizers: A review

Rock fertilizers are geological resources used in agriculture for their nutrient content, but slow weathering rates hinder their effectiveness. Carbonatites are igneous rocks made mostly of carbonate minerals with a relatively high weathering rate and often containing nutrient-bearing accessory minerals (e.g., apatite and biotite). Despite evidence supporting their potential as rock fertilizers, a comprehensive review of such data is missing in the literature. Furthermore, when studies on agricultural uses of carbonatites exist, they typically centre on applied research aspects (i.e., does it work?) rather than on basic research aspects (i.e., how does it work?). Here we evaluate the applicability of carbonatites in agriculture taking into consideration the factors that affect mineral weathering and plant nutrient uptake. While there are sufficient data to conclude that carbonatites can be a source of many plant nutrients, their effectiveness depends on the interactions of many components (e.g., soils, plants, microorganisms). To develop best management practices around carbonatites used in agriculture, it is essential to understand these interactions.