Irrigation has been surprisingly underplayed in sub-Saharan Africa despite renewed interest in agricultural development since the Maputo Declaration of 2003. Talk of a green revolution for Africa most often centres on improved soils, better seeds or more fertiliser.
This is surprising as few changes to farming hold as much promise as irrigation. It can increase yields and production, protect against yield losses to variable rains, and enable cultivation in dry seasons and of potentially high-value crops that consume more water. Crop yields in sub-Saharan Africa are often compared unfavourably to those seen in Asia. Yet Asia has 30 per cent of its arable land irrigated, compared to 6 per cent or less in sub-Saharan Africa.
Bad investment experiences may account for this. From the 1950s to the 1970s, ambitious large-scale publicly-operated irrigation projects were launched across Africa. By the 1980s, however, too many had failed at a high cost. One response was to hand over the management of such schemes to water-user groups. But putting farmers in charge didn’t reduce the high costs of some schemes, nor did it resolve problems in scheme design and operation.
Despite this, a new review from the DFID-ESRC Growth Research Programme (DEGRP) shows informal irrigation initiated by farmers has been thriving. Farmers have seized the opportunity attracted by the chance to sell high-value crops to expanding cities and encouraged by increasingly available and affordable equipment – above all small diesel and petrol pumps. They have diverted water from rivers and reservoirs on to their fields, or have pumped water from reservoirs, lakes, and wells.
Consequently, irrigation may have expanded much more than official statistics report. For example, radar images of flooded rice fields in Shinyanga, Tanzania, show ten times the area under irrigation than officially recorded. In Ghana, estimates imply that six times the area officially recorded may be irrigated.
This should be welcome news. Not all irrigation delivers the benefits expected, but the incomplete, fragmented evidence shows that often it does: production and productivity rise on fields, farmers – both men and women – earn more, and the local economy and workforce benefits from linkages in input supply and the processing and marketing of crops.
Socially, informal irrigators vary – some water small plots using buckets or watering cans – lacking capital and time to irrigate more. Their irrigation may not produce much in total, but supplements otherwise insufficient incomes. Others operate on a wholly different scale. They divert or pump water on to their land, hire labour, grow and market vegetables and other high-value crops, and achieve gross returns worth thousands of dollars a year.
Farmer-led initiatives also have drawbacks. They may deprive other downstream users of water or lower groundwater levels. Extensive water consumption may also affect ecosystems within water catchments. Also, irrigators may take over uncropped, common land used for grazing or collecting, undermining livelihoods.
Two challenges stand out for policy-makers. The first is to support farmer-led initiatives where it leads to a net benefit. This could mean improving roads to areas with irrigation potential or removing other market impediments. It may also entail finding ways to assist those who have not been able to take up the chance to irrigate.
To do this, the extent, nature and diversity of farmer-led irrigation must be appreciated. A broad menu of policies and public investments are needed – rather than, for example, small projects that centre on a specific technology that suit some irrigators, but not all.
The second challenge is regulation, to ensure that irrigation does not harm the environment, over-abstract from the catchment, or deny water to others – above all domestic water users. This is easy to state, but hard to put into practice.
The track record of water regulation and allocation is decidedly mixed. Water catchments do not usually correspond to administrative and political divisions. Farmers who have invested in irrigation on their initiative do not want their use of water changed by regulators. Finding ways to regulate fairly and effectively will almost always require adaptation to local circumstances, but it would help if working models were better known.
The challenges change through time. In early stages, with little irrigation in the catchment, the public role is to create conditions that allow farmers to irrigate. As more and more farmers take up irrigation, the priority is to assist those who have not been able to adopt. When irrigation become widespread with much use of water, fair regulation and water-sharing become critical.
Much of the interest in irrigation focuses on ‘modern’ technologies – drip and sprinkler irrigation, solar pumps, etc. – to extract more water, make better use of it and reduce costs. While such advances are welcome, the greater challenge is finding effective ways to assist farmers irrigating using surface water, while regulating where and when necessary.
This may not be straightforward, but the rewards promise to be high. If just 15 per cent of fields in sub-Saharan Africa were irrigated, double the current area, the contribution to agricultural production and rural incomes would be immense.