Irrigation practices in smallholder farming systems and their implications for crop productivity and household dietary diversity: A review

Abstract:

How effectively can irrigation reshape both the quantity and quality of food reaching rural households in sub-Saharan Africa? This review examined published evidence on the relationship between irrigation practices in smallholder farming systems and two linked outcomes: crop productivity and household dietary diversity. Literature from East, West and Southern African agroecological zones was retrieved through systematic searches of Scopus, Web of Science and CAB Abstracts covering the period 2010 to 2024. Furrow, basin, sprinkler and drip technologies were assessed alongside rain-fed controls. Results from 47 peer-reviewed articles and institutional reports indicated that supplemental irrigation raised cereal grain yields by 38 to 127 percent relative to rain-fed baselines, with drip systems providing the highest water-use efficiency at 14.6 kg m⁻³. Irrigated households cultivated 2.3 more crop species on average and achieved dietary diversity scores 1.4 to 2.9 points above non-irrigated counterparts on the Household Dietary Diversity Score scale. Constraints included high capital cost of pressurised systems, unreliable energy supply and gender-related access barriers. The evidence confirms that well-targeted irrigation investment can simultaneously lift yields and broaden the dietary base of smallholder families, although affordability and institutional support remain decisive factors.