Evaluation of soil hydraulic properties under different non-agricultural land use patterns in a basement complex area using multivariate statistical analysis.

Abstract

The knowledge about effects of different land use patterns on soil hydraulic properties is essential for best land management practices. This study examined hydraulic properties under different non-agricultural land uses in parts of Abeokuta, Southwest Nigeria. Fifteen clusters surface soil samples at a depth of 0-20cm were collected from five sites on the same geological setting under the following land uses: grassland (control), dumpsite (DS), animal waste site (AWS), quarry site (QS), and block making site (BMS). The calculated values of associated hydraulic properties and Ksat were used to develop three model equations. Pearson's correlation, coefficient of variation (CV), analysis of variance (ANOVA), cluster analysis (CA), and principal component analysis (PCA) were used to study the variations and correlation of analyzed soil properties under different land uses. Porosity and water holding capacity (WHC) of all the other land uses were increased relative to the control site (CS) while soil bulk density (BD) in control was reduced when compared to soils under other different land use patterns. However, BMS and QS increased Ksat relative to the CS. Soils in all land use patterns belong to sandy loam except CS. Correlation coefficient revealed a strong negative correlation between BD and porosity and strong positive correlation between % clay and WHC. Comparison among the regression models showed that Ksat predicted from semi-log model with R2 = 0.645 estimated better than both linear and double-long models. The use of PCA resulted in four principal factors accounting for 97.24% of the total variance. The result of CA shows groups based on similar soil hydraulic property, distinct soil property value, and erosional indicator. ANOVA showed that there was significant difference at 5% level (P < 0.05) among all selected land use patterns with respect to BD and porosity. This indicates that BD and porosity can be considered as dynamic soil hydraulic indicators that are strongly affected by land use systems.