EFFECTS OF TILLAGE SYSTEM ON PROPERTIES OF AN ALFISOL IN SOUTH-WEST NIGERIA
Keywords:
Seedbed preparation, tillage, total porosity, hydraulic conductivity, infiltration rateAbstract
The effects of seven years of no-tillage with crop residue mulch on soil physical and chemical properties was compared with that of the conventional seedbed preparation involving ploughing and harrowing for an Alfisol in Southwest Nigeria. These observations were made on soil samples obtained from the long-term tillage plots established at the experimental farm of the international Institute of Tropical Agriculture since 1971. Soil bulk density toalporosity, resistance to penetrometer, and saturated hydraulic conductivity were more favourable in no tillage than in ploughed plots. The water runoff was 11 and 74 mm with corresponding class of 320 and 2800kg/ha season for no-tillage and conventionally ploughed plots, respectively. Higher infiltration rate, and therefore less runoff and erosion, on no-tillage plots was partly attributed to favourable soil structure created by high earthworm activity. Earthworm casts amounted to 2020/m2 and 860/m2 in 80 days for no-tillage and conventionally ploughed plots, respectively. The surface layer of untilled plots contained higher concentration of organic carbon, total nitrogen, and exchangeable cations than that or the ploughed plots.