Spatial analysis of soil physicochemical and hydraulic properties in the Libga irrigation scheme in northern Ghana using geostatistics and GIS approach

Abstract

This study was undertaken to determine the spatial variability of soil physicochemical and hydraulic properties in the Libga irrigation scheme in order to make appropriate recommendations for site-specific management on irrigation and soil/plant nutrition. Soil samples were collected from 0-30 cm and 30-60 cm depths from 50 geo-referenced points located at the nodes of a 100 m × 100 m regular grid. Particle size distribution (PSD), bulk density (BD), total porosity (TP), field capacity (FC), permanent wilting point (PWP), available water capacity (AWC), saturated hydraulic conductivity (Ksat), electrical conductivity (EC) and pH were determined following standard laboratory protocols at the AGSSIP Laboratory of the University for Development Studies, Nyankpala. Generally, soils in the scheme had relatively high bulk densities and were slightly acidic. Electrical conductivity displayed the highest variability with CVs of 154.6% at 0-30 cm and 178.7% at 30-60 cm whereas BD displayed the lowest variability (CVs of 4.43% and 4.8% at 0-30 cm and 30-60 cm). Most of the soil properties exhibited moderate to strong spatial dependence indicating that they were mainly influenced by intrinsic or soil forming factors. Spatially, the soil properties showed a continuous distribution pattern over relatively longer distances indicating that site-specific irrigation and fertilization could be implemented in the scheme.