Evaluation of lime requirement tests for minesoils

Evaluation of twelve minesoils collected from restored or abandoned surface mines in eastern Kentucky with six standard lime requirement procedures showed that one of the procedures accurately forecasted long term lime requirements. The minesoils were then evaluated for potassium choloride-extractable aluminum using the Yang exchangeable acidity procedure. When the extractable A1³⁺ was multiplied by a factor of 2.24 it was found to also be an accurate measure for longterm limestone requirements. To bring the minesoil to pH 5.5 the results obtained using the modified Yuan procedure indicate that for each MEQ Al³⁺ extracted per 100 grams of minesoil 2.24 Mg of calcium carbonate (CaCO₃) equivalent lime per hectare be applied. Application of lime based on this procedure and one of the standard lime procedures resulted in pH stability of the minesoils for forty months.