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Small-scale irrigation investments needed in sub-Saharan Africa

Agricultural productivity in sub-Saharan Africa remains significantly less than the rest of the world, and 25 percent of people in the region still suffer from an insufficient dietary intake of calories. Yet sub-Saharan Africa has more arable land than Asia or Latin America, and a more diverse set of cereal grains. Agriculture also accounts for 20-25 percent of GDP for the region compared with only five percent for the rest of the world.

So why is productivity in sub-Saharan Africa so low when agriculture is such a big part of the economy, asked Rosamond L. Naylor, director of the Center on Food Security Environment at last week’s Connecting the Dots conference. Lack of irrigation is part of the problem. 95 percent of farms in sub-Saharan Africa are rainfed and rely on water from a short, 4-5 month rainy season. 

“During the rainy season kids are fed pretty well,” explained Naylor. “But during the peak of the dry season up to one-third of children are severely malnourished in parts of West Africa where we have been working.”

Sub-Saharan Africa has largely missed out on the benefits of the Green Revolution that increased crop production in Asia two to three fold. Asia’s heavily irrigated agriculture took advantage of new crop varieties that were bred to take up nutrients with sufficient water availability. Groundwater sources in sub-Saharan Africa, on the other hand, are more fractured and not well understood, and surface water isn’t necessarily close to where the people are.

“But Africa has water” said Naylor. “Groundwater resources have not been sufficiently explored and rivers such as the Nile and Niger remain underutilized due to a mindset that irrigation systems must be large scale.”

This requires big investments and institutional involvement that have thus far not resulted in great payoffs. Corruption in some areas coupled with institutional and tribal issues have also contributed to failed investments.

“We need to change our investment strategies from large-scale to small-scale irrigation systems,” suggested Naylor. “Evaluate the returns from treadle, solar-power, and diesel pumps to see what works where, so that we stop investments that aren’t working and support investments where they are.”

Treadle pumps can work well if they are close to surface water, but require a lot of labor, explained Naylor. There is a huge energetic cost and an opportunity cost for someone to work the treadle pump, so it is necessary to ‘get the right technology to suit the water and labor conditions’.

Irrigation is not just about access (drawing water). It is also necessary to think about how to best distribute that water to crops (e.g. drip irrigation) and what you use them on. Production of leafy greens, for example, leads to higher income and nutritional returns.

FSE’s solar market garden project in Benin is a good example of where appropriate technologies are being applied in a cost-effective manner. Solar-powered, drip irrigation pumps have improved incomes and nutrition for participating farming groups through the year-round production of high-value crops. Proven to be a viable and profitable investment, the project is now scaling up in other villages in Benin and West Africa.

“According to the World Bank, investment in agriculture is the best bang for your buck than any other investment,” said panel moderator Jenna Davis, assistant professor in the department of civil and environmental engineering and affiliated FSE fellow.

Fortunately, the World Bank is beginning to recognize the viability and efficiency of investments in small-scale irrigation projects. NGOs and academia also have a role to play in facilitating these projects. Through these partnerships and shifts in investment strategies, the development community has a better chance of improving access to freshwater resources for some of the world’s most vulnerable and effectively addressing sub-Saharan Africa's water and food security crisis.