SOIL-WATER DYNAMICS UNDER CEREAL AND FORAGE LEGUME MIXTURES ON DRAINED VERTISOLS IN THE ETHIOPIAN HIGHLANDS

At the Debre Zeit Station cereals (wheat and maize) and forage legumes (lablab, cowpea, vetch and clover) were grown as sole crops and as ce real/forage combinations on the broadbeds separated by drainage furrow s (BBF). This is an improved land management system, developed by ILCA in collaboration with other national and international partners, to r aise productivity of Vertisols. Soil water content monitored at soil d epths of 0-50 cm and 50-100 cm indicated that lablab and cowpea deplet e significantly greater amounts of available soil water during the gro wing season than vetch and clover. Deep rooted forage legumes lablab, cowpea and vetch are more suitable for combination with cereals such a s maize than with wheat due to the phenological differences between th e two crop types. Grain yields of wheat and maize were higher when int ercropped with legumes than as sole crops in the absence of external N input. Moisture use by the various crop-forage land use types are dis cussed.