Making every drop count
Simple, sustainable solutions in agricultural water management
A variety of simple, affordable techniques can increase food production for small-scale farmers without excessive water withdrawals or damage to the environment.
“Some practices that require no investment can be very effective, but farmers need to know about them,” says Pasquale Steduto, Chief of FAO’s Water Development and Management Unit. “Well-functioning extension services can help promote water-saving techniques and improve efficiency.”
Water harvesting -- irrigating crops with on-farm rainwater runoff -- can significantly improve both yields and the reliability of agricultural production.
Drip irrigation, which directs water only where and when it is needed, is more efficient than flooding fields and using sprinklers. Results from a number of countries show that farmers who switched from sprinkler irrigation to drip systems have cut their water use by 30 to 60 percent. “Spoon-feeding” the optimal amount of water, and sometimes fertilizer, to crops when and where they need it often increases yields at the same time.
Avoiding excessive application of pesticides and fertilizers has a direct impact on water quality and people's health.
Inexpensive, human-powered treadle pumps, which extract irrigation water from shallow aquifers, have increased poor farmers’ productivity in many Asian and African countries. The farmer has full control over the timing and the amount of water pumped which, given the effort involved, is used sparingly. Small motor pumps have also revolutionized small-scale horticulture around cities.
Recycling of treated wastewater for use in irrigation is another option with enormous potential benefits, especially in light of rapid urbanization. A city with a population of 500 000 and water consumption of 120 litres per person a day produces about 48 000 cubic metres of wastewater a day. When treated, this wastewater could be used to irrigate around 500 hectares. The nutrients in effluent are almost as valuable as the water itself. Typical concentrations in treated wastewater effluent from conventional sewage could provide all the nitrogen and much of the phosphorus and potassium normally required for agricultural crop production.
Changes in crops and dietary choices can also have an impact on water usage. Policies that encourage people to eat less water-intensive foods - wheat rather than rice, poultry rather than beef, for example - can increase water efficiency markedly. Countries with limited water resources might prioritize production of agricultural commodities requiring relatively little water and import those requiring more water.
“The knowledge exists to improve water use,” says Steduto. “And the potential gains are wide-ranging – employment, environmental sustainability, socioeconomic benefits. The limiting factor is implementation. People need incentives to use water more efficiently.”
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