Smart Agricultural Watering Merging Earth Observation and Meteo-Station Data
Gomez Cid, Celestino; De la Fuente, David

The agricultural region of Lower Rioja, in Spain, is a major national orchard and fruit producer within this economic sector. In 2010, 101.085ha were productive, of which, 15.800 ha were exploited under irrigated conditions. Most common crops are herbaceous -cereals-, together with a variety of orchard and woody crops –vine, pear, apple, peach-. Fertile alluvial soils developed on the Ebro river sediments allow sound yielding's per irrigated hectare: apple 22,9Tn/ha; pear 21,19Tn/ha; grape 6,44Tn/ha; artichoke 12,1Tn/ha.
Seasonal yielding varies dramatically as a result of the wide inter-annual oscillations of rainfall and temperature (e.g. total rainfall 2008 = 630mm; 2009 = 366mm), characteristic of the dominant continental Mediterranean climate. Critical weather events affecting plant yielding are late spring and early summer heat spills, coincident with the ripening period of most orchard and woody crops.
Woody crop producers have verified the results obtained during 2011 by the smart agricultural watering service provided by GMV. The service alerts of turnkey moments to amend the planned irrigation calendar; management options may bring forward water surplus due to plant stress or delay it, on account exceeding soil moisture.
Baseline data has a dual origin, in situ and remote: (i) 34 field weather stations provide 15 minute interval agro-meteorological data automatically retrieved and processed. The meteo-series is built up during the whole phenologic cycle (215 days). The series allows deriving two key parameters: evapotranspiration (following FAO's dual method) and daily soil moisture balance. (ii) Daily MODIS data, checked against historical series, are processed to retrieve weekly NDVI composites and relative greenness index. MODIS data are used to adjust FAO’s standard crop transpiration coefficient (kcb) to determine the actual phenologic stage of the crop.
Reports delivered to producers include daily, weekly and fortnight soil moisture balances; these three temporal scales of the service allow interpreting extreme daily moisture behaviors and normalized tendencies. Results include cartographic outputs, graphs and charts, easy to read and interpret by the crop producer.