Satellite-based irrigation advisory services: A common tool for different experiences from Europe to Australia

Earth Observation techniques are widely recognised in supporting the management of land and water resources and they are nowadays being transferred to operative applications. In this paper, we present the current status of a satellite-based irrigation advisory system based on dedicated webGIS or farmers and district managers, in three different agricultural systems and environments: Southern Italy, Austria and Southern Australia. Maps of canopy development (leaf area index, albedo and soil cover) are derived from high-resolution (20 m) multispectral satellite images, delivered in near real time (24–36 h) and processed by using in-situ agro-meteorological data. The outputs of this procedure are: (i) a personalised irrigation advice, based on the calculation of crop evapotranspiration under standard conditions (according to FAO-56 definition and by using the direct approach) by taking into account the actual canopy development and crop variability at sub-plot scale; (ii) timely delivery of the information, consisting in maps and suggested irrigation volume applications, timely published on a dedicated webGIS-site with access restricted to growers and basin authorities in order to better control the irrigation process and consequently improve its overall efficiency. The key-points of this procedure are: (a) personalised irrigation advice; (b) timely delivery of the information. Final users have provided important feedback on the usage of the information provided; i.e. farmers are able to recognise without difficulties their parcels on the images and they schedule the irrigations by taking into account the information provided. The crop heterogeneity captured by the high resolution images is considered as a valuable add-on information to identify the variability of soil texture and fertility, plant nutrition, or different performance of irrigation systems. All the farmers have evaluated positively the usefulness of the information provided, and in most cases an increase of irrigation efficiency was achieved, because of the reduction of water volumes.