By Justus Wanzala

Fri Sep 9, 2016 3:06pm GMT

STOCKHOLM, Sept 9 (Thomson Reuters Foundation) - Sub-Saharan Africa is seeing a surge of interest in irrigation among small-scale farmers as climate change brings more erratic weather and as rising populations in countries from Nigeria to Kenya mean demand for a reliable harvest is growing, agriculture and water experts say.

The International Food Policy Research Institute (IFPRI) estimates that more than a million hectares of small farms are now irrigated in the region, based on limited government data and satellite images.

In Tanzania, the area of small farms with access to irrigation has risen from just 33,500 hectares in 2010 to about 150,000 today, institute figures show. But up to 29 million hectares in the East African nation alone potentially could be irrigated, said Ruth Meinzen-Dick, an IFPRI researcher.

Boosts in irrigation could help protect the region's food security in the face of more extreme weather conditions driven by climate change, and be an engine of development, she and other experts said at the recent World Water Week gathering in Stockholm.

"Small-holder farmers' irrigation is a climate resilience option," said Dawit Mekonnen, an IFPRI researcher based in Ethiopia.

SCALING UP

Increases in irrigation have been driven not only by more extreme weather conditions but by growing access over the last decade to more affordable Chinese-made water pumps, said Jennie Barron, a sustainable water researcher with the International Water Management Institute.

But expanding access to irrigation to a much higher number of farmers will require a range of other changes, from cuts to taxes on imported irrigation equipment to better training of farmers - particularly women - in the latest irrigation techniques, the researchers said.

Ensuring women - who make up about half of Africa's agricultural labour force - have legal ownership of farmland is also key to ensuring they feel confident in making costly investments in irrigation, the experts said.

"Women are more disadvantaged because they lack control over assets," Barron said.

Mekonnen said access to irrigation is increasingly key to helping farmers in countries such as Ethiopia, Ghana and Tanzania provide enough food for their families throughout the year and get ahead financially by selling produce at dry times of year when demand and prices are highest.

ROADBLOCKS

One problem, he said, is that most sub-Saharan African countries have not yet mapped their most easily accessible groundwater resources, which makes it hard for small farmers to know what water is available.

Boosting rainwater harvesting and building small dams to capture runoff may help many farmers in areas where groundwater is limited, the experts said.

Because pumping water requires energy, helping small-scale farmers get access to clean renewable energy, such as solar or wind power, will also be key to helping them afford to irrigate, Mekonnen said.

Revolving funds - in which members join savings clubs and pool money to make loans to each other - and micro-credit loans also will be key to help small farmers afford irrigation equipment, the experts said.

But Tim Prewitt, the chief executive officer of charity organisation International Development Enterprises (iDE), said that financing of irrigation for small-scale farmers remains a challenge, in his organisation's experience.

"In Ghana we started working with 12 micro-finance organisations but only two are still with us," he said, in part because of problems ranging from defaults to high administrative costs.

According to IWMI, only 7 percent of sub-Saharan Africa's farmland is irrigated, the lowest proportion of irrigation anywhere in the world.

(Reporting by Justus Wanzala; editing by Laurie Goering :; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, climate change, women's rights, trafficking and property rights. Visit news.trust.org/climate)