Maize (Zea mays) is among the major cereals
grown in the high rainfall areas of the subSaharan
Africa’s (SSA) such as the Ethiopian
part of the Blue Nile basin. However, its productivity
is severely constrained by poor soil,
water and crop management practices. This
study simulated water productivity of the crop
under varying soil fertility scenarios (poor, near
optimal and non limiting) using hybrid seeds
under rainfed conditions using the FAO AquaCrop
model. The result indicated that grain yield
of maize increased from 2.5 tons·ha–1 under
poor to 6.4 and 9.2 tons·ha–1 with near optimal
and non-limiting soil fertility conditions. Correspondingly,
soil evaporation decreased from 446
mm to 285 and 204 mm, while transpiration
increased from 146 to 268 and 355 mm. Consequently,
grain water productivity was increased
by 48% and 54%, respectively, with the near
optimal and non-limiting soil fertility conditions.
The water productivity gain mainly comes from
reduced evaporation and increased transpiration
without significantly affecting water left
for downstream ecosystem services. Therefore,
this has a huge implication for a basin scale
water management planning for various purposes.