Abstract:
Improving irrigation management in semi-arid regions of Sub-Saharan Africa is crucial
to respond to increasing variability in rainfall and overcome deficits in current irrigation schemes.
In small-scale and medium-scale reservoir-based irrigation schemes in the Upper East region of Ghana,
we explored options for improving the traditional, dry season irrigation practices and assessed the
potential for supplemental irrigation in the rainy season. The AquaCrop model was used to (i) assess
current water management in the typical tomato-maize rotational system; (ii) develop an improved
irrigation schedule for dry season cultivation of tomato; and (iii) determine the requirement for
supplemental irrigation of maize in the rainy season under different climate scenarios. The improved
irrigation schedule for dry season tomato cultivation would result in a water saving of 130–1325 mm
compared to traditional irrigation practices, accompanied by approximately a 4–14% increase in
tomato yield. The supplemental irrigation of maize would require 107–126 mm of water in periods of
low rainfall and frequent dry spells, and 88–105 mm in periods of high rainfall and rare dry spells.
Therefore, year-round irrigated crop production may be feasible, using water saved during dry
season tomato cultivation for supplemental irrigation of maize in the rainy season.
