Potato and water resources
Agriculture must significantly improve its volume of production per unit of water used.
The potato produces more food per unit of water than any other major crop.
From the same water amount, the potato produces more energy than rice, wheat and maize (above).
Over the past century, human appropriation of freshwater has expanded at more than twice the rate of population increase. An estimated 3 830 cubic km (that's 3 830 000 000 000 000 litres) of water are now withdrawn for human use each year, with the lion's share – some 70 percent – being taken by the agricultural sector.
But agriculture's thirst is not sustainable in the long term. Facing intense competition from urban and industrial users, and mounting evidence that human use of water is jeopardizing the efficiency of the Earth's ecosystems, the sector must significantly improve its volume of production per unit of water used.
The potato stands out for its productive water use, yielding more food per unit of water than any other major crop. Along with groundnut, onion and carrots, its "nutritional productivity" is especially high: for every cubic metre of water applied in cultivation, the potato produces 5 600 calories (kcal) of dietary energy, compared to 3 860 in maize, 2 300 in wheat and just 2 000 in rice. For the same cubic metre, the potato yields 150 g of protein, double that of wheat and maize, and 540 mg of calcium, double that of wheat and four times that of rice.
An increase in the proportion of potato in the diet would alleviate pressure on water resources. Currently, producing the foods – especially animal products – consumed in the average diet in the developed world requires water withdrawals estimated at 4 000 litres per capita per day (it takes, for example, around 13 000 to 15 000 litres of water to produce 1 kg of grain-fed beef). But one recent study estimated that a balanced diet based on potato, groundnut, onion and carrot would require per capita water consumption of just 1 000 litres per day.
While a potato-based diet is impractical – 4 kg would be needed to cover per capita daily energy and protein requirements – increased consumption of processed potato products and extraction of potato's nutrients offer a water-efficient means of meeting nutritional needs.This factsheet is based on information provided by FAO's Land and Water Division.