Spatial Variability of Soil Chemical Properties of an Undulating Site within a University Farm at Okha, near Benin City in Nigeria

Abstract

Assessment of spatial variability of soil properties due to inherent factors is critical for optimum crop production and environment protection. Hence, the objectives of this study was to evaluate the influence of climate, topography and land management on spatial variability of the soil chemical properties and fertility status of an undulating farmland at Okha, near Benin City. Twelve soil samples were collected from the depth of 0-20 cm at an interval of 30 m × 30 m on a regular grid design with a global positioning system and assessed using standard methods. Results revealed that the coefficient of variability (CV) was low for sand and clay (<15 %), moderate for silt (15 – 50 %), low for pH, moderate for organic C, N, K and ECEC but high for P (>50%). The soil texture was sandy loam and pH displayed very strongly, strongly as well as medium acid conditions.  Concentrations of organic C were generally low, N and P were low, while K was very low. Low concentrations of ECEC were spread over the site with highest concentrations on the concave part of the landscape. Generated maps revealed a substantial influence of topography and land use on spatial variability of soil chemical properties even within a small part of a farmland which is quite useful for site-specific nutrient management.