Abstract:
While the world population is expected to reach 9 billion in 2050, inWest Africa, it will more
than double. This situation will lead to a high demand for cereals in the region. At the same time,
farmers are experiencing yield losses due to erratic rainfall. To come up with a sound and e ective
solution, the available but limited water should be used to achieve high yields through irrigation.
Therefore, full and deficit irrigation management strategies were evaluated. The expected profit that
can be obtained by a smallholder farmer under a conventional irrigation system in the short-term
of investment was also assessed considering rope and bucket, treadle pump, and motorized pump
water-lifting methods. The study focused on maize in northern Togo. The framework used in
this study consisted of (i) a weather generator for simulating long-term climate time series; (ii) the
AquaCrop model, which was used to simulate crop yield response to water; and (iii) a problem-specific
algorithm for optimal irrigation scheduling with limited water supply. Results showed high variability
in rainfall during the wet season leading to significant variability in the expected yield under rainfed
conditions. This variability was substantially reduced when supplemental irrigation was applied.
This holds for the irrigation management strategies evaluated in the dry season. Farmers’expected
net incomes were US$ 133.35 and 78.11 per hectare for treadle pump and rope and bucket methods,
respectively, under 10% exceedance probability. The motorized pump method is not appropriate for
smallholder farmers in the short run.
