Abstract
In this study, the yield response of maize species was investigated under different irrigation levels and techniques. Three
irrigation treatments compared were T1) Control in which the needs of the plants for water were fully met; T2) Partial-rootdrying (PRD) treatment where the same amount of water that was applied under the DI (i.e., 65% of that applied under control
treatment) was applied to wet alternately only one halve of the plant roots leaving the other half dry in each irrigation; T3)
Deficit Irrigation (DI) which received 65% of total water needed by the control. However; both halves of the plant roots were
equally wetted under the deficit irrigation treatment, T3. Therefore, the wetted side changed in every irrigation under the PRD
treatment. The data obtained in PRD and DI plots were compared to those in control treatment. The maize crop yields followed
the rank T1>T2>T3. The water-use efficiency (WUE) was the highest under the PRD treatment. Crop response factors (Ky)
changed within the range from 0.75 to 1.37 under the PRD treatment, from 1.13 to 1.78 under the DI treatment. The Ky data
therefore suggested that deficit irrigation under the PRD technique caused proportionally less crop yield decrease as compared
to the DI technique. The mid-day leave water potential (LWP) data was influenced essentially by the practices not with the
crop species. The predawn LWP values increased as the soil water content increased with the irrigation. Under the DI treatment,
water stress was more evident compared to the other treatments. It was noted that plants showed better capability for surviving
water stress if irrigated with the PRD practice. The maize, to this effect, showed specie-dependence. The species Tector and
Tietar were selected as the best species, showing no significant yield decrease under the deficit irrigation if irrigated with the
PRD.
