Water: The source of life and a precious resource for agriculture

Water is essential for economic and social development. Although a large part of the earth’s surface is covered by water, water is only then an exploitable resource when it is suitable for consumption either by humans, industry or agriculture. Most of the freshwater is used for agricultural purposes, like irrigation. In fact, agriculture accounts for 70 per cent of all withdrawals, a figure that increases to 95 per cent in developing countries.
FAO brochure 'Water at a Glance'

These figures may seem high, but these amounts of water are actually needed to produce enough food for the world’s fast-growing population. According to the FAO , an additional 14 per cent will be needed for agriculture in order to achieve the necessary 55 per cent increase in food production by 2030. Over the next 50 years, water shortages in agriculture are predicted to be the single biggest constraint facing food production.

Irrigated farm-land doubled over last 50 years

While the daily requirements of drinking water per person is only two to four litres, the production of 1,000 kilojoules of food requires on average of 83 litres of water. For example, to produce one apple needs 70 litres of water. However, calculating and assessing the water use for food production is difficult, as it depends on the source / origin of water and the local water availability. It is important to make the distinction between rain-fed agriculture - farming that depends on natural rainfall - and irrigated agriculture. Irrigating land changes the natural water cycle, through withdrawal of water from surface or groundwater and use for growing crops in intensive systems. Rain-fed agriculture in contrast relies on the natural climate conditions and has no direct impact on the water cycle; it is therefore more vulnerable to the impact of adverse weather and climate change and tends to be less productive.

Irrigation has made a huge contribution to providing a stable food supply for the world’s population. Over the last 50 years, the Earth's population has doubled, with the global food system responding remarkably to this increase in food demand. While total cropland increased by only 12 per cent over this period, the irrigated area doubled, accounting for most of the net increase in food production.

Increasing water efficiency in agriculture necessary

Technology in agriculture can help save water – either directly through better irrigation systems or by planting crops that require less water, or indirectly via yield-increasing products and methods. Each year, 20 to 40 per cent of worldwide crops are lost due to competing weeds, pests and plant diseases. Reducing these losses either through optimized crop protection or increased drought tolerance of the crops through breeding or genetic modification would increase the yield per unit of water (water use efficiency). Other possibilities include making changes in dietary and cropping choices to focus on such crops and food that use less water and finally, also avoiding wasting food, as this also means a waste of water.

Good water quality needs to be maintained

Nevertheless, it is important to stress that we also need to safeguard water quality in agriculture, particularly when intensive production systems are predominantly used. Proper use of crop protection products, such as avoiding spillages and a prudent use of fertilizers, play a key role in maintaining good chemical water quality. Another important factor relevant to water quality is making water usable for people, for example by using filtration to remove bacteria from drinking water. Last but not least, mosquitoes and other insects that breed in water can threaten human health by spreading diseases like malaria or dengue fever. Water purification solutions can play an important role in ensuring that water bodies are a healthy drinking water resource without being a reservoir for waterborne diseases.