Abstract:
Rice is one of the major staple foods in sub-Saharan Africa (SSA) and is mainly grown in
three environments: rainfed upland and rainfed and irrigated lowlands. In all rice-growing
environments, the yield gap (the difference between the potential yield in irrigated lowland or
water-limited yield in rainfed lowland and upland and the actual yield obtained by farmers) is
largely due to a wide range of constraints including water-related issues. This paper aims to review
water management research for rice cultivation in SSA. Major water-related constraints to rice
production include drought, flooding, iron toxicity, and soil salinity.
A wide range of technologies has been tested by Africa Rice Center (AfricaRice) and its
partners for their potential to address some of the water-related challenges across SSA. In the
irrigated lowlands, the system of rice intensification and alternate wetting and drying significantly
reduced water use, while the pre-conditions to maintain grain yield and quality compared to
continuous flooding were identified. Salinity problems caused by the standing water layer could
be addressed by flushing and leaching. In the rainfed lowlands, water control structures, Sawah
rice production system, and the Smart-Valleys approach for land and water development improved
water availability and grain yield compared to traditional water management practices. In the
rainfed uplands, supplemental irrigation, mulching, and conservation agriculture mitigated the
effects of drought on rice yield. The Participatory Learning and Action Research (PLAR) approach
was developed to work with and educate communities to help them implement improved water
management technologies.
Most of the research assessed a few indicators such as rice yield, water use, water
productivity at the field level. There has been limited research on the cost-benefit of water
management technologies, enabling conditions and business models for their large-scale adoption,
as well as their impact on farmers’ livelihoods, particularly on women and youth. Besides, limited
research has been conducted on water management design for crop diversification, landscape-level water management, and iron toxicity mitigation, particularly in lowlands. Filling these research
gaps could contribute to sustainable water resources management and sustainable intensification
of rice-based systems in SSA.
