Chima Njoku

Department of Soil Science and Environmental Management, Faculty of Agriculture and Natural Resources Management, Ebonyi State University, P.M.B. 053, Abakaliki, Nigeria

Abstract

The aim of this study was to determine the physical and chemical properties of soil as affected by flood and erosion in Abakaliki Southeastern Nigeria. Sites selected for the study were: Control (arable land), fallowed floodplain, cultivated floodplain and erosion site. Five auger and core replicate soil samples were collected from each site at the depth of 0 – 30 cm and analysed for particle size distribution, bulk density, total porosity, moisture content, dispersion ratio, modified clay ratio, erosion ratio, erodibility factor, soil loss, lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), ammonium (NH₄⁺), nitrate (NO₃^–), sulphate (SO₄^2-) and organic matter. Results from the study showed that the experimental sites were sandy loams which are easily vulnerable to erosion as a result of its properties. Physical properties indicated that the order of susceptibility to erosion was arable land < fallowed floodplain < cultivated floodplain < erosion site. The results of chemical properties showed that cations such as NH₄⁺ were higher in floodplains than arable land whereas anions such as NO₃^– and SO₄^2- were higher in arable land than floodplains. This phenomenon might be attributed to the fact that unlike NH₄⁺ which binds strongly to clay micelle, NO₃^– and SO₄^2- are anions and can be easily leached beneath root zone (0-30 cm) because of their negative charges. Moreover, the erosion site had the poorest fertility and productive status when compared to other sites.  The results also, showed that the floodplains have inherent capacity to boost crop productivity and the nutrients leached during flooding can be recovered through fallowing the floodplains for some periods before using them for crop production.

Keywords: Erosion, Deposition, Floodplain, Leaching and transportation