Effects of Lime and Phosphorus Applications on Soil Chemical Composition, Growth and Nutrient Uptake of Maize (Zea mays L.) in an Acid Soil of Gununo, Southern Ethiopia

Soil acidity and phosphorus deficiency are some of the constraints affecting crop production in highlands of Ethiopia. A pot experiment was conducted with maize (Zea mays L. ACV 6) to determine the effects of lime (CaCO3) and phosphorus (P) application on highly acidic and P-deficient clayey soil from Gununo area in southern Ethiopia. The experiment consisted application of lime at three rates (0, 3, and 6 g CaCO3 kg-1 soil) and P at four rates (0, 50, 100 and 150 mg P kg-1 soil), each quadruplicated in a completely randomized design (CRD). Plants harvested at 60 days after plating were partitioned into roots and shoots to record dry matter yields. Changes in soil properties and macronutrient concentrations in roots and shoots were determined. Application of the lime at the highest tested rate (6 g CaCO3 kg-1 soil) increased the soil pH by 1.73 units over control, and increased the concentrations of Ca and Mg in the soil and plants. Liming, when applied with P, also improved dry matter production and P concentration in shoots. However, liming alone did not influence available P in the experimental soil, and increasing rates of lime resulted in a slight decline in plant growth and biomass production. On the other hand, P application significantly enhanced available P and exchangeable Ca in the soil; plant heights, root and shoot dry weights, and uptake and concentration of nutrients in shoots and roots. Interestingly, application of 50 g P kg-1 soil improved root and shoot dry weights by 1332 and 4184%, respectively, as compared to controls (P omitted pots) demonstrating that P was a more important limiting nutrient for maize growth in the study soils. The results demonstrated that 3 g CaCO3 kg-1 together with 50 g P kg-1 soil could be recommended for maize growth on the acidic soils of the Gununo area, Boloso Sore district of southern Ethiopia.