STANFORD—Rural farmers in sub-Saharan Africa live under risky conditions. Many grow low-value cereal crops that depend on a short rainy season. A lack of rain can trap them in poverty and hunger.
Reliable access to water could change the farmers’ perilous situation. Stanford scientists are calling for investments in small-scale irrigation projects and hydrologic mapping to help buffer the in the face of climate change in the region.
“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,”said Jennifer Burney, a fellow at Stanford’sCenter on Food Security and Environment. Her team partnered with the Solar Electric Light Fund (SELF) to measure economic and nutritional impacts of solar-powered drip-irrigated gardens on villages in West Africa’s Sudano-Sahel region. Burney will present the group’s work on small-scale irrigation Wednesday, Dec. 7, at the fall meeting of the American Geophysical Union in San Francisco.
Modern irrigation often means multi-billion-dollar projects like damming rivers and building canals. But Burney says that these projects have not reached sub-Saharan Africa because countries lack the capital and ability to carry out big infrastructure projects. Today, only 4% of cropland in sub-Saharan Africa is irrigated.
Irrigation 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.
Burney and her colleagues’ work in two northern Benin villages with women’s cooperative agricultural groups to install three solar-powered drip irrigation systems that conserve water and 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 and even realize money 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 said.
For solar technology projects to be successful, Burney said, just 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. But solar is only one answer. “Solar is great if you have an unreliable fuel,” she said. “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 said. “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 transition zone between the Sahara Desert and the savannas further south.
Given the diversity of water resources in West Africa, Burney suggests that nongovernmental organizations and governments 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 said.
Burney says that 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 said. Having more disposable income also will reduce vulnerability to hunger and malnutrition. “Economic development can be a form of adaptation,” she said.
Rosamond Naylor, director of Stanford’s Center on Food Security and the Environment, and Sandra Postel of the Global Water Policy Project collaborated on the project.
—Sarah Jane Keller is a science-writing intern at the Stanford News Service.
Also on Stanford Knowledgebase: