Department of Soil Science, Ambrose Alli University, Ekpoma, Nigeria.
The hydroxy-Al and hydroxy-Fe coating on clays regulate to a large degree of the chemical and physical properties of Ultisols and Oxisols. Liming of Ultisols and Oxisols to pH 7 and above often decrease plant growth and reduces nutrient availability. The best way to minimize over liming problems is to lime to eliminate toxic levels of Al and Mn from the soil solution and colloid surfaces. To apply more lime than this is probably unnecessary, wasteful, and can be detrimental to crop growth and the efficient utilization of other production inputs.
