ZERO-TILLAGE AND INTERCROPPING ON A TROPICAL ALFISOL: EFFECTS ON SOIL PHYSICAL PROPERTIES

Abstract

Rapid deterioration of soil physical properties of arable land under continuous cultivation adversely affects crop production in the humid and sub-humid tropics. This investigation, which lasted for four consecutive growing seasons, was conducted to determine whether the deterioration can be minimized by a tillage and cropping system that can be readily adopted by the local farmer. The results show that over the four growing seasons, soil bulk density (Db) of the surface (0 - 0.lm) soil increased by 0.10Mg/m³. Intercropping reduced soil compaction rates under conventional tillage (CT) and No-tillage (NT) in the two years while sole crops of maize and melon increased soil compaction in their respective plots under CT. Surface soil of the NT plots retained more water than that of CT plots at saturation and field capacity. Higher saturated hydraulic conductivity (SCH), and improved infiltration characteristics were found under NT. Intercropping with melon was effective in improving soil physical properties under both tillage treatments. The over-all results indicate improvement in soil physical properties under NT and intercropping with continuous cultivation. It further shows the possibility of integration of NT into the subsistence intercropping farming methods practised in this region where fertilizers and weed control chemicals are just gaining popularity.