Water is a natural resource which is essential for life.The reserve of existing global freshwater is very low when compared to the mass of salt water that covers 70% of the globe. This freshwater is unevenly distributed and scarce. In 60 years, consumption has increased six-fold.
Worldwide, 71% of the available water (rain, soil reserves) is used for crop irrigation. This scarcity, coupled with population growth, creates a challenge which must be overcome: to double food production by 2030, while consuming less water - despite the many constraints, such as urbanization, industrialization and climate change.
So how should we manage this resource while ensuring its quantity and quality, the sustainability of agricultural systems and the protection of the environment?
Water is facing three major problems in the world: pollution, waste, and scarcity in the face of growing demand.
Farmed or grazed soils are generally rich in fertilizers, and some of these nutrients can be found in surface and groundwater. There is also water loss in irrigation systems and over-consumption despite more frequent droughts.
An FAO analysis covering 93 developing countries showed that 18 of them use irrigation on more than 40% of their cultivated land (FAO, World Agriculture: Towards 2015/2030). According to the FAO, a country is said to be experiencing water-stress if it takes more than 20% of its renewable water resources. By this definition, over 20% of the countries were already water-stressed in 1998.
Solutions to conserve water
There are solutions to save water and reduce pollution. Micro-irrigation (drip irrigation), which provides just the necessary amount of water by watering at the base of the plant, is an efficient system. Moreover, it maintains soil moisture and reduced the necessity of frequent watering. It is also worthwhile to store and recycle discharge water using dams.
Changes in farming methods are necessary: in times of drought, changing the duration of the crop cycle adjusts to the available water, or choosing a crop variety which is more tolerant to water stress. It is advisable to choose synthetic fertilizers, organic matter, and more generally, return to the seasonality of crops.
Thus, to reconcile production needs, the availability of water resources and increased droughts, it is important to manage water use by varying its uses, improving its quality and preserving aquatic environments and the benefits they provide.