Determination of the Effect of Changes in Climatic Factors on the Variations in Soil Physicochemical Properties of Farm Settlements located in Ogun State, Nigeria

The study of the response of soil to climate change is of fundamental importance for sustainability of life through agriculture. This paper determines variations in physicochemical properties of farm settlements soils, assesses the effect of changes in climatic factors (temperature, relative humidity, and rain-fall) on these soil physicochemical properties and its implication on plant growth. Soil samples were collected from two farm settlements in the major geological zones in Ogun State Southwest, Nigeria. Physicochemical properties of the collected soil samples were determined using standard methods and metrological data were collected from metrological offices in the state. The result of the soil physicochemical properties ranges between; 5.84-6.39 (pH), 14.6-24.9 g/kg (organic carbon (O.C)), 15.9-19.9 mg/kg (phosphorus), 0.99-1.90 g/kg (nitrogen), 2.95-10.3 cmol/kg (cation exchange capacity (CEC)), 0.21-0.33 (exchangeable acidity), 78.1-89.2 (% sand), 5.70-10.2 (% clay) and 4.18-11.8 (% silt). Significant seasonal variations were found in the results obtained from the two farm settlements in properties like: pH, organic carbon and N at 0.05%. Higher C/N ratio recorded in some of the analysed soils may lead to the release of CO₂ which is a greenhouse gas. Variations observed in all the climatic factors considered in this study with O.C, CEC, % clay and % silt at p<0.01 can be used to assess the effect of climate change on soil health and assist in devising climate adaptive strategies. In other to reduce the negative implication of these variations on plant growth, irrigation facilities must be provided in the studied farms.

Keywords
Physicochemical properties; farm settlements; arable cropping; permanent cropping