Small-scale irrigation: ‘Ladder out of poverty’

STANFORD (US) — Investments in small-scale irrigation and geophysical mapping will help relieve food insecurity in sub-Saharan Africa, researchers say.

Rural farmers in the region live under risky conditions because many grow low-value cereal crops that depend on a short rainy season, a practice that can trap them in poverty and hunger. But reliable access to water could change the farmers’ situation and help buffer them from erratic weather and poor crop yields that are expected to worsen with climate change.

“Irrigation is really appealing in that it lets you do a lot of things to break this cycle of low productivity that leads to low income and malnutrition,” says Jennifer Burney, a fellow at the Center on Food Security and Environment at Stanford University.

Burney partnered with the Solar Electric Light Fund to measure the economic and nutritional impacts of solar-powered, drip-irrigated gardens on villages in West Africa’s Sudano-Sahel region. Burney presented the group’s work on small-scale irrigation this week at the fall meeting of the American Geophysical Union in San Francisco.


Drip irrigation conserves water by delivering it directly to the base of the plant. (Credit:Jennifer Burney)

Modern irrigation often means multi-billion-dollar projects like damming rivers and building canals. But these projects have not reached sub-Saharan Africa because countries lack the capital and ability to carry out big infrastructure projects.

A different approach, gaining popularity in sub-Saharan Africa, involves cooperation. Individuals or groups, called smallholders, organize to farm small plots and ensure their access to irrigation. These projects allow farmers to grow during the dry season and produce profitable, high-nutrition crops like fruits and vegetables in addition to the cereal crops they already grow.

Smallholder irrigation

The work Burney and her colleagues have done in two northern Benin villages is an example of successful investment in smallholder irrigation. They worked with women’s cooperative agricultural groups to install three solar-powered drip irrigation systems. Drip irrigation—that conserves water by delivering it directly to the base of plants—also reduces fertilizer runoff.

The team surveyed 30 households in each village and found that solar drip irrigation increased standards of living and increased vegetable consumption to the U.S. Department of Agriculture’s recommended daily allowance. By selling the vegetables, households were able to purchase staples and meat during the dry season.

Successful smallholder irrigation projects have high investment returns. Burney has seen real success from irrigation projects—like those in Benin—that provide enough returns for women to send kids to school or buy small business equipment like a sewing machine or market stall.

“That’s when I think it really becomes a ladder out of poverty,” Burney says.

Lessons for success

For solar technology projects to be successful, dropping in and giving people irrigation kits doesn’t work. Communities need access to a water source and need to see the benefits of a project.

“You need the technology and management and the water access, all together,” says Burney. “Our solar project incorporates all of that.”

Smallholders need not limit themselves to solar irrigation systems. “Solar is great if you have an unreliable fuel,” she says. “But if you’re someplace that’s connected to the grid, an electrical pump would more economical.”

“There are a lot of different solutions that involve many different kinds of water harvesting,” Burney says. “Groundwater, rainwater, surface water, and there are a lot of places in the Sahel, like Niger, for example, where there are artesian wells.” The Sahel is a transitional belt of grasslands between the Sahara Desert and the savannas further south.

Given the diversity of water resources in West Africa, nongovernmental organizations and governments should prioritize detailed hydrologic mapping in the region. Otherwise, the cost of geophysical surveys and finding water sources, especially unseen groundwater, could become an insurmountable barrier for farm communities.

“It needs to be really detailed, comprehensive, usable information that’s out there for everybody to be able to take advantage of,” she says.

Both of the benefits that farmers get from irrigation systems—growing outside of the rainy season and producing more diverse, profitable crops—are important for adapting to climate change.

“You can produce more value on less land in most cases and not be as beholden to the whims of the rainy season,” she says. Having more disposable income also will reduce vulnerability to hunger and malnutrition. “Economic development can be a form of adaptation.”

Rosamond Naylor, director of Stanford’s Center on Food Security and the Environment, and Sandra Postel of the Global Water Policy Project were collaborators on the project.

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