DETERMINATION OF PERMEABILITY OF SOILS FROM FUNAAB AGRICULTURAL LAND USE, USING IMPROVISED CONSTANT HEADPERMEAMETER

Abstract

The knowledge of material property of the pore space through which water flow in soil for the optimization of water supplies for agricultural and engineering projects is fast becoming challenging due to intricate geometries of the media porous structures. The study determines the permeability coefficients of soils at six different Federal University of Agriculture, Abeokuta, (FUNAAB) land-use (Hostel-Site, Cashew Plantation, FADAMA Farm, COLPLANT Farm, Forest nursery unit, FUNAAB health center) in order to estimate the flow rate through the soil using an improvised constant head permeameter. The soils were initially analyzed for their physical properties before determining the flow rate and permeability coefficients.  The reliability of result of permeameter was compared with standards for validity. The result shows that the soils were slightly acidic with pH average of 6.8, organic carbon ranging from 0.78% to 4.49% with the highest at the Fadama site. The total nitrogen ranged between 0.1% and 8.0% and the available phosphorus ranged between 1.20 to 3.95 mg kg^-1 with the highest value experienced at cashew plantation. The improvised permeameter gave a reliable result with high positive correlation in volume rate of flow in soil and time of flow. The permeability coefficient of the soil samples (K) were in the range of 2.7 x 10^-5to 4.2 x 10^-5with the soil type ranging from sandy-loam to loamy sand similar to the result obtained during physical analysis. The soils were of relative permeability of semi-pervious, a characteristic of poor soil transmissivity.