Comparative Effects of Lime and Phosphorus Sources on Nutrients Uptake and Yield of Maize in a Tropical Ultisol

Ultisols are acid forest soils of low fertility status formed from intense weathering and leaching processes in the humid temperate and tropical regions. Sustainable crop production on these soils where phosphorus (P) deficiency is a main constraint aims at maintaining high crop yields by enhancing nutrients availability and uptake efficiency. This study was carried out at the Faculty of Agriculture, University of Ibadan to compare nutrients uptake and yield among maize plants grown from an ultisol with either sole or combined amendments of lime (L), rock phosphate (RP) and organomineral fertilizer (OMF). Eight treatment combinations: control, L, RP, OMF, L+ RP, L+OMF, RP+OMF and L+RP+OMF, each supplying 200kg P/ha and/or 1.0t/ha of L were replicated three times in a Complete Randomized Design. Crops grown in the RP+OMF amended soil (AMS) took up the highest concentrations of Ca, Zn, Mn and Fe. These were followed by the uptake of Ca and Mn from the L+RP AMS with the highest uptake of Mg. Next were those produced from the OMF AMS for Mg, Ca, Mn with the uptake of Zn and Fe only second to those in the RP+OMF AMS. Maize produced at 4 weeks after sowing from the OMF and L+RP AMS took up relatively higher concentrations of P, and together with those raised in the RP+OMF AMS which had the heaviest significant (P≤0.05) fresh root weight, produced the most significant height, leaf area and fresh shoot weight. The concentrations (1.10g/kg) of the dried shoot weight of the OMF and L+RP AMS were significantly higher than those of the other AMS, besides that of the RP+OMF (0.98g/kg). Tropical ultisols could be amended with OMF, RP+OMF or L+RP for effective nutrient uptake and maize yield.