Measuring how efficiently water is used in agriculture, particularly in water-scarce countries, is going high-tech with the help of a new tool developed by the Food and Agriculture Organization of the United Nations (FAO).
The WaPOR open-access database is tapping satellite data to help farmers achieve more reliable
agricultural yields and optimise irrigation systems, FAO reported in April 2017. WaPOR allows for a fine-grained analysis of the water utilised through farming systems, generating empirical evidence about how it can be most productively used.
WaPOR sifts through satellite data and uses Google Earth computing power to produce maps that show how much biomass and yield is produced per cubic meter of water consumed. The maps can be rendered at resolutions of as little as 30 to 250 meters, and updated every one to ten days.
The WaPOR tool, being developed in cooperation with a consortium of partners in The Netherlands - eLEAF, University of Twente, ITC and Waterwatch Foundation - as well as VITO in Belgium, is to cover Africa and the Near East, with a focus on key countries that are or are projected soon to face physical or infrastructural water scarcity.
The continental-level database is online since April, while country-level data will be made available in June for Benin, Burundi, Egypt, Ethiopia, Ghana, Jordan, Kenya, Lebanon, Mali, Morocco, Mozambique, Rwanda, South Sudan, Syria, Tunisia, Uganda, West Bank and Gaza Strip, and Yemen. Even more detailed data will come online in October, starting with pilot areas in Lebanon, Ethiopia and Mali.
Measuring the water consumed by a crop
WaPOR measures evapotranspiration, a key phase in the natural water cycle consisting of water that directly evaporates into the atmosphere and water that returns to the atmosphere after moving through a plant and emerging as vapor exuded by foliage. Evapotranspiration thus provides a direct measure of the water consumed by a crop during a growing season and, when related to the biomass and harvestable crop yield, makes it possible to calculate crop-water productivity.
The tool can produce detailed assessments to monitor the functioning of a selected set of irriga-tion schemes, supporting modernisation plans as well as helping assure that improvements do in fact result in all water users receiving more reliable and cost-effective water services that are more adapted to increased climate variability.
The program uses a pixel-based methodology to produce comprehensive maps allowing for better use of natural resources. When coupled with real-time data, agricultural extension agents can help farmers obtain more reliable crop yields, both improving their livelihoods and making them more sustainable.
The IHE Delft Institute for Water Education, part of UNESCO and the world's largest international graduate water education facility, and the International Water Management Institute (IWMI) will support efforts in developing countries to boost capacity to use the new technology - by tailoring relevant direct data queries, conducting time series analyses and downloading data regarding key variables that contribute to water and land productivity assessments.