Prediction of characteristics of coastal plain soils using terrain attributes

Abstract

The objective of this study was to model the characteristics of coastal plain sands using terrain attributes. Representative surface soil samples of upper, middle and lower slopes were collected from 10 locations and their properties determined using standard laboratory methods. Soil properties determined include depth, sand, silt, clay, electrical and hydraulic conductivity, bulk density, pH, exchangeable calcium, magnesium, sodium, potassium and acidity, available phosphorus, organic carbon, base saturation, crystalline and amorphous iron and aluminium oxides. The terrain attributes derived from digital elevation model (DEM) include slope, aspect, curvatures, flow direction and hill shade, compound topographic index (CTI) and stream power index (SPI). Data generated were analysed using Pearson’s correlation and stepwise multiple regression analysis. Slope significantly correlated with clay and pH (H₂O), while SPI and CTI correlated significantly with clay, pH, organic carbon and crystalline iron oxide. Soil properties that could be predicted using terrain attributes include clay bulk density, pH, exchangeable acidity and amorphous aluminium oxides. Terrain attributes could be useful in the prediction and knowledge of soil distribution and variability for sustainable management and optimal crop production on coastal plain sands geomorphic units.

Keywords: coastal plain sands, DEM, soil characteristics, modelling