COMPARATIVE NONLINEAR MODELING OF NUTRIENT RELEASE KINETICS FROM SILICATE REMINERALIZERS FOR SUSTAINABLE SOIL MANAGEMENT

Soil remineralization with rock powders has re-emerged as a strategy to broaden gradual nutrient supply and reduce dependence on highly soluble fertilizers. Its agronomic and environmental usefulness, however, depends on kinetic models able to represent asymmetric trajectories and a realistic approach to release plateaus. Here, 210 observations arranged in 15 time series of Ca, Mg, [Formula: see text], Si, and [Formula: see text] release from basalt, biotite schist, and pegmatite were fitted with five nonlinear growth models (Logistic, Exponential, Gompertz, Richards, and Von Bertalanffy). Model performance was compared using [Formula: see text], RMSE, MAE, MAPE, AIC, and BIC. The Richards model yielded the highest [Formula: see text] in every series, with a mean of 0.9706, outperforming Gompertz (0.9412), Logistic (0.9287), Exponential (0.7862), and Von Bertalanffy (0.7619). The estimated parameters also revealed consistent contrasts among rocks and nutrients, especially for [Formula: see text], Si, and [Formula: see text], indicating that the additional shape flexibility becomes important when mineral dissolution reflects multiple overlapping processes. Overall, the results show that flexible sigmoidal models are useful for comparing remineralizers and supporting gradual nutrient-release strategies. All fit metrics and parameter estimates are reported in Appendix A.