CHANGES IN SURFACE SOIL PROPERTIES OF A NO-TILLED TROPICAL ALFISOL DUE TO INTERCROPPING MAIZE, CASSAVA AND EGUSI MELON

Changes in earthworm activity, water runoff, soil erosion, soil physic al properties and fertility, and crop growth and yield caused by inter cropping either maize (Zea mays L.) and cassava (Manihot esculenta Cra ntz) (MC) or maize, cassava and 'egusi' melon (Citrullus lanatus Thunb .) (MCM) on no-tilled and handhoe-tilled plots were studied in an Alfi sol in southwestern Nigeria. Runoff and erosion in no-tilled plots wer e negligible and were not affected by cropping system. Similarly, soil compaction and infiltration which were lower and higher, respectively , in no-tilled plots than in tilled plots were also unaffected by crop ping system. With tillage, however, MCM resulted in lower penetrometer resistance in die soil surface and erosion than MC, although water in filtration was unaffected. Maximum diurnal soil temperatures were lowe r with MCM, with lowest values being observed when combined with no-ti llage. Similarly, soil fertility was greater with MCM, with highest fe rtility occurring in no-tilled plots. Combination of no-tillage with M CM resulted, therefore, in a soil environment which was least compacte d, most fertile, cooler, had higher water infiltration rates and where water runoff and soil erosion rates were negligible. Inclusion of mel on in the crop mixture did not affect grain yield of maize, but reduce d cassava tuber yield. Reduction in tuber yield was of the order of 19 %.