INFILTRATION CHARACTERISTICS OF A TYPIC HAPLUSTULT UNDER DIVERSE TILLAGE PRACTICES AND COVER CROPS IN NORTHERN GUINEA SAVANNA OF NIGERIA

Abstract

Soil tillage and vegetation cover impact a great deal on hydrological processes in soil. However, there exist a dearth of literature on the extent of these effects in semi-arid Nigeria. This study investigated the effect of tillage practices (no-till, (NT) reduced till (RT) and conventional tillage (CT)) and cover crops (Centrosema pascuorum (CP), Macrotyloma uniflorum (MU), Glycine max (GM), Cucurbita maxima (CM) and no cover crop (bare) as control) on soil water infiltration rate and characteristics. A double ring infiltrometer was used to carryout infiltration study of soils under the aforementioned tillage practices and cover crops. Data obtained were used to calculate infiltration rate and these were also fitted into the Philip and Kostiakov’s models. The quality of adjustment of the models was verified by a chi square and T test, coefficient of determination (r2) and standard deviation. Result revealed higher infiltration rate in soil under conservation tillage (NT and RT) due to soil pores continuity, than in the CT where the pores had been disrupted by tillage implement. Similarly, the use of any of the evaluated cover crops improved water infiltration better than the bare soil with no cover crop. Conservation tillage system (RT and NT) favoured better soil infiltration rate by 41.25% and 29.53% respectively more than conventional tillage system. Plots with cover crops had 65.27%, 59.46%, 54.88% and 18.9% higher soil water infiltration rate in CP, MU, GM and CM treatments respectively than the bare (no cover crop) treatment. Both Kostiakov and Philip’s model were suitable for predicting the first one-minute infiltration rate. However, Kostiakov’s equation showed superior performance over Philip’s equation, in determining cumulative infiltration, this was evident from the lower standard deviation and CV values of Kostiakov’s parameters. In addition to the general non-significance differences obtained between measured and Kostiakov’s predicted infiltration values as revealed by Chi square test.