Description and Nutrient Management of Upland and Lowland Soils in Abeokuta, Southwestern Nigeria

Abstract

Field experiments were conducted to characterize lowland and upland soils and determine how their properties influence the effects of integrated nutrient management [INM] on soil productivity. One profile pit each was classified in the lower and upper slope positions where factorial experiments in randomized complete block design with three replicates werre established. The factors were poultry manure [0.5 and 10t ha], lime [CaCo3] [0 and 250kg ha] and NPK 15-15-15 [0 and 100 kg ha]. The profile pits differ morphologically in terms of horizon depths, colour and iron concretions. Soil organic carbon content which decreased with increasing depth ranged from 1,0-4.9 g kg in the lower slope and 1.8-25.5g kg in the upper slope soil. The mean clay dispersion radio value of 20.2% was obtained at lower slope against a value of 25.9%obtained at the upper slope in response to INM. Application of poultry manure [PM] with NPK fertilizer significantly raised soil saturated hydraulic and resulted in 40% and 59% increases in soil inflitration rate [IR] at the lower and upper slopes, respectively. The IR at the upper slope was higher than that of the lower slope by about 190%. Integrated application of PM, lime and NPK significantly raised soil chemical properties than the control at the both slope was higher at upper slope than lower slope in the most cases. Maize yeld was significantly raised with the use of PM, especially 10 t ha than the control and inorganic amendments while maize yield was highrer by 24% at the upper slope than the lower slope. Therefore, INM is a better option for improving maize yield, especially in soils dominated by non-expanding clay types