Comparison of Infiltration Rates of Soils for Run-Off Management and Irrigation Planning in Makurdi Benue State, Nigeria

Understanding of initial infiltration rates and steady state infiltration rates of soil is very important for runoff management and irrigation scheduling. Therefore, a field experiment was conducted at the Teaching and Research Farm of Joseph Sarwuan Tarka University, Makurdi in 2018 to evaluate the initial and steady state infiltration rates of soils in Makurdi, Nigeria. Infiltration test was carried out using double ring infiltrometer at eighteen points. Initial and steady state infiltration rates and the cumulative infiltration were then calculated. Soil samples were collected from the adjacent area of the marked points at 0-15 cm and 15-30 cm depths for routine analysis. Undisturbed soil samples were also collected for the measurement of saturated hydraulic conductivity, bulk density, total porosity and moisture content determination. Simple descriptive statistic of mean, variance and standard deviation was used to analyze the data. The soils were predominantly sandy loan texture, with percentage sand, silt and clay as 710.7, 118.9, and 170.4 g kg-1 respectively. Soil bulk density and saturated hydraulic conductivity were 1.40 g cm-3 and 10.27 cm hr-1 at 0 – 15 cm depth, while soil organic carbon and CEC were 0.67 % and 6.62 cmol/kg respectively. The initial infiltration rate ranged from 7.40 - 87.46 mm hr-1 with a mean of 44.09 mm hr-1, meanwhile, the steady state infiltration rate ranged between 4.99 – 22 mm hr-1, with a mean value of 15.42 mm hr-1. High soil bulk density caused moderate to low infiltration capacity. The mean values for the steady state infiltration rate suggest that the soils of the study area have moderate infiltration capacity, therefore, water application for irrigation should be less or equal to the infiltration capacity of the soils to minimize water loss by surface runoff and erosion.