Integrating Soil pH, Clay, and Neutralizing Value of Lime into a New Lime Requirement Model for Acidic Soils in China

Modelling the lime requirement (LR) is a fast and efficient way to determine the amount of lime required to obtain a pH that can overcome the adverse effects caused by soil acidification. This study aimed to model the LR based on the properties of soil and lime. A total of 17 acidic soils and 39 lime samples underwent soil–lime incubation in the laboratory. The predictive equations for the LR (t ha⁻¹) were modelled using ∆pH (the difference between the target pH and initial pH), the neutralizing value (NV, mmol kg⁻¹) of lime, soil pH, soil clay content (%), soil bulk density (BD, g cm⁻³), and the depth of soil (h, cm) as the factors in an exponential equation. The generic predictive equation, $\mathrm{L}\mathrm{R}=∆\mathrm{p}\mathrm{H}\times {\mathrm{e}}^{-3.88-0.069\times \mathrm{N}\mathrm{V}+0.51\times \mathrm{p}\mathrm{H}+0.025\times \mathrm{C}\mathrm{l}\mathrm{a}\mathrm{y}}\times \mathrm{B}\mathrm{D}\times \mathrm{h}$, was validated as the most reliable model under field conditions. Simplified predictive equations for different soil textures when limed with quicklime and limestone are also provided. Furthermore, the LR proportions provided by hydrated lime, quicklime, limestone, and dolomite in commercially available lime can be expressed as 0.58:0.64:0.97:1.00. This study provides a novel and robust model for predicting the amount of lime product containing components with different neutralizing abilities that are required to neutralize soils with a wide range of properties. It is of great significance to agronomic activities and soil remediation projects.