The Use of Automated Weather Stations for Irrigation Management In the Jordan Valley.

We discuss an irrigation management information system approach developed by NCARE researchers with the help of USDA-ARS. The system is capable of providing farmers with online crop water requirements based on automated meteorological data published on the internet (www.ncare.gov.jo/imis, and www.merimis.org). Since 2003, this Middle Eastern Regional Irrigation Management Information Systems (MERIMIS) project has focused on improving irrigation scheduling in Jordan, Palestine, and Israel with cooperators from the region and the U.S. These efforts have established a network of 15 weather stations to support an irrigation scheduling service using the paradigm that crop water use (ETc) is equal to a reference evapotranspiration (ETr) value (calculated from weather data) multiplied by a crop coefficient (Kc) obtained from FAO paper number 56. A weighing lysimeter was constructed in the Jordan Valley in order to determine ETc and update Kc values for the specific and unusual climate there; and an eddy covariance station was also used to this end. So far, ETc data have been measured for sweet corn, onion and tomato. Since 30% of the cultivated area in the Jordan Valley is occupied by plastic houses, separate studies of crop water use in plastic houses were instituted, showing that water use was greatly reduced while crop yield and quality improved. The ETc system is similar to several international networks, such as the California Irrigation Management Information System (www.cimis.org), which provide crop water requirement values based on climatic data and ETr estimation methods such as the Penman Montieth equation. The online network can provide farmers with accurate irrigation water requirements, and consequently can save up to 20% of the normally applied irrigation water, with better water management. The system is also modified to provide the farmers with on farm crop water requirements using SMS mobile service text messages.