Statistical analyses of variability in properties of soils in gully erosion areas of Agulu-Nanka-Oko, Southeastern Nigeria.

Abstract

The study involved the statistical analyses of variability of soil with depth and its influence on gully development. The soil data were obtained from field study and laboratory analyses. The statistical analyses of soil data were performed on soil index properties using Statistical Package for Social Sciences.
Results of the analysis of variance and Duncan Multiple Range Test (DMRT) indicate that there are significant differences (P<0.001) in soil properties with sampling depth. The moisture content and degree of saturation were the most varied with depth with coefficient of variation (CV) ranging from 34% to 38% and 32% to 38% respectively. The underlying soils are essentially sand with some fines. The sand fractions range from 70% to 84% and fines (particle size fraction less than 0.075mm) range from 12% to 29%. The maximum dry densities and bulk densities of the underlying soils range from1850kg/m3 to 1992kg/m3 and 1532 kg/m3 to 1650 kg/m3 respectively. The wide disparity between maximum dry densities and field bulk densities suggests that the natural deposits were loose. This condition is favourable for easy soil dispersal. The low amount of fines (silt/clay) in the underlying substrata implies insufficient binding material and thereby suggests high susceptibility of the underlying soil materials to erosion.


Keywords: gully, soil, erosion, statistical analysis,

Journal of Mining and Geology Vol. 43 (2) 2007: pp. 197-202