Monitoring water use in agriculture through satellite remote sensing
Mr. Jippe Hoogeveen
Senior Land and Water Officer, Land and Water Division, UN Food & Agriculture Organization (FAO)
Achieving food security in the future while using water resources in a sustainable manner is a major challenge for us and future generations.
In 2050, food needs to be produced for an expected population of between 9 and 10 billion people.
A lot of water is needed to produce food.
Irrigated agriculture, as it is practiced today, is responsible for 70% of all freshwater withdrawals in the world. Not all of this water is actually used by the crops. A large part of this water, in traditional systems often more 50% is not evaporated by the plants and flows back to rivers or groundwater. This water can be used again by water users downstream.
How to monitor the performance of water
A careful monitoring of water productivity in agriculture, that is the amount of crop which can be produced by using a certain amount of water, is required to increase water productivity. But how can we monitor the performance of water use in agriculture? How can we increase water productivity in the future to make sure we grow more crop per drop?
New developments in earth observation technology indicates that nowadays it is feasible to monitor key data for sustainable agricultural production and natural resources management using satellite remote sensing.
Evapotranspiration is the process that includes both evaporation of water from the soil, canopy interception and water bodies, as well as transpiration from plants. This can be quantified by using satellites. Likewise, plant growth can be assessed by using satellite remote sensing.
If we manage to increase the amount of biomass produced by a crop or decrease the amount of water used, then we increase water productivity. As such, we contribute to both more sustainable water use in agriculture as well as food security for a growing population.
Irrigated agriculture is responsible for 70% of all freshwater withdrawals in the world.
Bringing this into practice.
Several satellites, from both NASA and the ESA provide free global data on spatial resolutions varying from tens to hundreds of meters being updated in time steps of one to 10 days. FAO brings this data together in its open access WaPOR data base to help farmers achieve more reliable agricultural yields and allowing for the optimisation of irrigation systems.
When being used on a high resolution, WaPOR can produce detailed maps to monitor the functioning of irrigation schemes to support modernisation plans and provide better water services to irrigators.
Agricultural extension services can use the data to support farmers to prevent crop failure, and as such, improving the livelihoods of smallholder farmers and making them more resilient to climate change.