The Hydraulic Conductivity of Soils under Continuous Maize (Zea May) Cultivation

Abstract

The severity and scope of our modern day practices in the last few centuries on the hydraulic conductivity of soil has affected its ability to control water infiltration and surface runoff. Soils exposed to human impact are often stripped of the organic-rich upper horizons, thereby increasing bulk density and reducing soil porosity. The study saw to determine the effects of continuous cultivation on the hydraulic conductivity, bulk density and porosity of soil. The hydraulic conductivity was measured with ring infiltrometer. Hydraulic conductivity was observed to decrease with increasing years of soils cultivation indicating a high impact of land use on this soil property. Hydraulic conductivity (K_s) values of 0.189±0.020cmh^-1, 0.162±0.023cmh^-1, 0.097±0.011cmh^-1, and 0.078±0.028cmh^-1 were respectively recorded for undisturbed forest, one year cultivated soil, two years cultivated soil and three years cultivated soil. The dry bulk densities obtained in forested soils, one year cultivated soil, two years continuous cultivated soils and three years continuously cultivate soil were 0.991±0.047gcm^-3, 1.025±0.031gcm^-3, 1.215±0.102gcm^-3, and 1.332±0.074gcm^-3 respectively with the least occurring on forest soils owing to high organic matter content and abundant burrowing fauna. To conclude, the study revealed that soil hydraulic conductivity, bulk density and porosity are time-variant and this fact should not be neglected in soil water flow modeling.

Keywords: Hydraulic conductivity, bulk density, porosity and continuous cultivation