Evaluation of Lime Application on Soil pH and Maize Performance in Acidic Soils of Abia State, South East Nigeria

This study evaluates the effect of different lime rates on soil pH correction and maize crop performance on strongly acidic soils in Abia State, located in Nigeria's South East geopolitical zone. Soil acidity is the most widespread soil fertility constraint in Abia State, where highly weathered Ultisols and Oxisols dominate the landscape with pH values commonly below 5.0, causing aluminium and manganese toxicity that significantly limits crop yields. A field experiment was conducted using a randomised complete block design with five lime rates applied as agricultural lime (CaCO3): 0, 0.5, 1.0, 2.0, and 3.0 tonnes per hectare, plus a positive control receiving recommended NPK fertiliser without lime. Lime was applied 30 days before planting to allow equilibration. Soil pH was measured before application, at planting, and at harvest. Maize was planted with uniform NPK fertiliser application across all lime treatments, and yield parameters including plant height, ear length, and grain yield per hectare were measured. Findings revealed that lime at 2.0 tonnes per hectare raised soil pH from 4.6 to 6.1 and produced the highest maize grain yield of 3.4 tonnes per hectare, representing a 188 percent yield increase over the unlimed control. Exchangeable aluminium was reduced to non-toxic levels at lime rates above 1.0 tonne per hectare. The study recommends 2.0 tonnes per hectare agricultural lime as the practical liming rate for maize production in Abia State, with three-year reapplication intervals to sustain pH correction. Keywords: lime application, soil acidity, maize yield, Abia State, aluminium toxicity.