THE FIRST year of providing a variable rate nitrogen application service using satellite imagery has gone successfully, according to SOYL.

Nitrogen savings from using the system should cover the average £6/ha cost, but cloudy conditions still present some users with problems acquiring images on time, said the firm’s Simon Griffin.

The system uses optical satellite images for first, second and third N applications, to measure the leaf area index of crops, which is then used to provide Leaf Area Index and N application maps, he explained.

Maps were successfully delivered to 100% of customers during the first application, 90% during the second and 80% by the third, he said.

“Many growers were able to reduce second N application rates due to high residual soil N following the relatively dry winter. We wait to see how these N savings will be reflected in yields.”

Next year, the company is planning to develop a web-based option for the service which will enable customers to download their LAI and N application maps online. Growers will receive an email alert when their maps are available, he added.