A first review on irrigation water requirement and withdrawal took place around the year 2000 within the framework of the preparation of FAO's global perspective study "World agriculture: towards 2015/2030" which included 90 developing countries and countries in transition. In 2012, AQUASTAT undertook an update of the modelling of the global irrigation water use. The spatial coverage of the data in the updated review consists of 165 countries (more than 80% of the countries in existence as of 2012), corresponding to those practicing irrigation and for which data on irrigated areas and on irrigated crops (around 60) were available.
The calendars refer to the years for which data was available. A detailed description of the methodology used is available on the Modelling of global irrigation water use section.
Irrigated crop calendars are available in the database along with their respective narratives.
Data availability and data reliability vary from one country to the other. To get more background, reference is made to the Discussion page of the above mentioned review.
The update frequency of the irrigated crop calendars in AQUASTAT is continuous, whenever new data becomes available, in particular during the country update which takes place once every 5 years at the most.
Quote as: FAO. [yyyy]. AQUASTAT - Irrigated crop calendars. Food and Agriculture Organization of the United Nations (FAO). Website accessed on [yyyy/mm/dd].
Info for all countries in the Irrigated Crop Calendars Database