Evaluation of Saturated Hydraulic Characteristics and its Influence on Some Physical and Chemical Properties of Soils Developed on Coastal Plain Sands of Obufa Esuk Orok in Calabar, Cross River State, Nigeria

Abstract

The study highlights the evaluation of saturated hydraulic characteristics and its influence on some physical and chemical properties of soils developed on coastal plain sands of Obufa Esuk Orok in Calabar, Cross River State, Nigeria. Sixteen grids designed in an experimental plot measured 6 m x 6 m were used for field studies and sixteen (16) soil samples were collected in each of the grid using a soil auger for particle size analysis, bulk density, particle density, total porosity and saturated hydraulic conductivity. The samples were analyzed using standard laboratory procedures. The result showed that the soils were predominantly high in sand content with a mean value of 860.6 g kg-1 and low in silt and clay contents with mean values of 56.1 g kg-1 and 83.3 g kg-1 respectively. The soil texture was predominantly loamy sand. The saturated hydraulic conductivity showed rapid with a mean value of 36 cm min-1. Total porosity was high, a mean value of 52.4 %. Bulk density was low, a mean value of 1.21 Mgm-3 while Particle density was moderate, mean value of 2.55 Mgm-3.  The soil pH showed very strongly acid milieu (mean pH in water = 5.1). Organic carbon and Total nitrogen were low with mean values of 1.1 % and 0.09 % respectively. Available phosphorus was high with a mean value of 36.66 mg kg-1. The exchangeable acidity and exchangeable bases were generally low with mean values of 2.54, 0.59, 0.08 and 0.053 cmolc/kg for calcium, magnesium, potassium and sodium and 0.261and 0.416 cmolc/kg for aluminum and hydrogen. The correlation coefficient (r) between the saturated hydraulic conductivity and texture showed that there was a positive relationship between saturated hydraulic conductivity and sand, silt and clay (correlation coefficient of r = 0.0013, 0.062 and 0.119) at p≤0.05 indicating good relationship. There was also a positive linear relationship between the saturated hydraulic conductivity and bulk density, particle density and total porosity (correlation coefficient values of r = 0.224, 0.03 and 0.107) at p≤0.05 respectively. Despite the positive relationship existed in their correlation, cultural practices such as minimum, zero, mulch tillage and other conservational practices should be adopted to help maintain the rapid condition of the saturated hydraulic conductivity to avoid restriction of water movement and other soluble nutrients in the soil.