The study showed that rainwater alone is not sufficient to support maize, which is the preferred staple food crop. Thus, a combination of improved tillage and rainwater harvesting techniques, which help to boost crop yields, needs to be employed. The study showed that with as little rainfall as 186-403 mm/season yields of up to 4.8 t ha can be achieved through the application of more efficient soil and water retention techniques compared to much less than 1 t ha as presently achieved. The study concluded that water is the limiting factor to productivity and that a combination of rainwater harvesting and conservation agriculture can contribute to improved grain yields by as much as 80%.