Comparison of Infiltration Rate and Hydraulic Conductivity of Three Dominant Soil Series for Irrigation Planning in Federal University of Agriculture, Abeokuta Southwestern Nigeria

Abstract

Infiltration rate and hydraulic conductivity are important hydraulic parameters for flow and transport related phenomena in soil, but results vary from different measuring methods and field conditions. To evaluate the reliability of field method using the double ring and laboratory methods using the falling head permeameter, Infiltration and hydraulic conductivity tests on the three dominant soil series in the Federal University of Agriculture, Abeokuta i.e. Ekiti, Iseyin and Iwo were investigated. The constants of linear regression of the infiltration rate were obtained using Kostiakov’s and Phillips equations as a and n to be 0.01 and 0.598 for Ekiti, 0.063 and 0.627 for Iseyin and 0.173 and 0.648 for Iwo soil series respectively. For Philip’s equation, a and b were found out to be 9.73 and 8.981 for Ekiti, 7.1 and 7.603 for Iseyin and 12.87 and 18.79 for Iwo soil series respectively. The average infiltration rates and cumulative infiltration were found to be 20.03, 15.93, and 34.77 cm/hr for Ekiti, Iseyin, and Iwo soil series respectively. The average values of hydraulic conductivity for Ekiti, Iseyin and Iwo were found to be 11.12, 10.07, and 22.6 cm/hr respectively. Iwo soil series was the most suitable for sprinkler irrigation due to its high infiltration rate while Ekiti and Iseyin soil series will suit drip irrigation adequately. This study also established that based on the derived relationships, permeability or hydraulic conductivity tests can be easily done in the laboratory rather than the cumbersome activity of carrying out infiltration on the field with a double ring infiltrometer.