Liming of Latosols and the Effect on Phosphorus Response

Studies were conducted with six Latosols from Panama to evaluate exchangeable Al as the criterion for determining lime rate and the effect of liming on P availability. Liming rates equivalent to exchangeable Al × 1.5 neutralized most of the exchangeable Al and adjusted pH to levels satisfactory for plant growth. Such liming rates were considerably less than those required to adjust the pH to 7. At low rates of applied P, liming to neutralize Al significantly increased growth of millet ( Pennisetum typhoides , var. Gahi 1), but had no beneficial effect if high rates of P were applied at < 60% Al saturation. However, liming significantly increased growth at all P rates if the Al saturation is > 60%.