Effects of tillage and intercropping on soil hydraulic properties, soil and water conservation and yield of maize (Zea mays L.).

Experiment was conducted on an alfisol at Ibadan located in the fringes of the rain forest. The mean annual rainfall is about 1270 mm. and there are two distinct wet (April to November) and dry seasons (December to March). There are two growing seasons. The first season from late March to late July ends in a short dry spell in August while the shorter second growing season begins in late August and ends in December. There were two main treatments: tillage and cropping patterns. The tillage treatments included (i) Conventional tillage (CT) and (ii) no-tillage (NT). The crop treatments included (i) sole maize (ii) sole melon (Colocynthis vulgaris) (iii) maize-melon intercrops and (iv) bare plots (control). There was a higher soil moisture retention especially at the high metric potential range under NT than CT. The increase in soil moisture retention induced by the melon either as sole crop or as intercrop with maize was slight but more noticeable in CT than NT a fact attributed to the extensive protective covering of the soil surface by the melon crop. The cumulative infiltration of the soil was 1.3 times higher on NT than CT plots. The cover crop did not appreciably improve the cumulative infiltration either as sole crop or as intercrops with maize although intercropping decreased slightly the reduction of infiltration rate over time on CT plots. Intercropping under NT plots resulted in higher soil water storage which was attributed to reduced evaporation rates effective smothering of weeds and improved soil conditions. Soil slumping and soil splash were similar in their responses to tillage treatments. Soil slumping was 3 times higher and soil splash was 2 times higher on CT than NT plots. The melon crop either as sole or mixed crops decreased appreciably soil slumping and soil splash. Although better soil physical conditions and reduced soil splash were obtained on NT plots than CT plots, these were not adequately reflected in the growth parameters of the crops. The mean maize grain yields were 2.50 t/ha on NT and 2.12 t/ha on CT plots. Intercropping melon with maize reduced the yield of melon but improved the yield of maize.