At the series of GRDC Updates earlier this year we were fortunate to hear about the use of satellite imagery in European farming practices. It has proved to be a very powerful tool for farmers and their advisers, with some 6000 European farmers set to use the FARMSTAR service provided by the space company EADS Astrium in 2005.

FARMSTAR is also being used in Australia, although in our case some of the information maps provided by the service are still being evaluated for their accuracy. Jon Medway of Terrabyte Services at Wagga Wagga says about 50,000 hectares of grain crops - mainly wheat and canola - right across Australia will be 'imaged' this year in addition to rice and cotton crops.

Australia is apparently well-suited to this technology - our farms and paddocks are larger than those in Europe, making for more economic use of the service, and the generally dry climate allows for good image acquisition by the FARMSTAR satellites.

The cost of the service in Europe is $15/ha for a package of three image dates, however its been demonstrated that European farmers can achieve a $25/ha net benefit. Mr Medway says Australian farmers are looking at less than $4/ha for a single image date and $7/ha for a two-image package. While it is too early to put a figure on the potential net benefit for Australian croppers, rice growers have achieved yield benefits resulting in an additional $150/ha with targeted nitrogen management.

FARMSTAR satellite images provide precise measurements of the biophysical characteristics of a crop - the leaf area index (LAI) and chlorophyll content - and from this data the plant population, biomass and nitrogen uptake status of the crop can be accurately determined. From this point, farmers are provided with crop management recommendation and information maps for tiller density, lodging risk and nitrogen application.

The service is complementary to other satellite-based farm management tools. For example, using variable rate technology and GPS, a grower can download the information and match fertiliser application precisely to the needs of the crop. The information can be used to indicate if a crop is stressed, it's yield potential, for irrigation scheduling or to determine the lodging risk. It is evident there is great potential for substantial savings for growers on their farm inputs, and to maximise a crop's potential cost-effectively.

While an introductory LAI service is commercially available to growers this season, Terrabyte Services is currently validating the more advanced agronomic packages for release in 2006 with conventional crop monitoring in the form of soil and tissue testing as well as aerial surveys and consultation with growers and agronomic advisers.

Jon says too many other remote sensing services have been hampered by a lack of validation and that it's important to be cautious and ensure the satellite imagery is accurate.