19 June 1998

On-line for field nutrient data

CEREAL growers who are connected to the Internet, have access to yield maps and are equipped with a GPS-controlled variable rate spreader or sprayer will soon be able to exploit two new services from Hydro Agri.

NPK-Online aims to bring the nutritional status of fields up to non-limiting levels, so crop growth is not starved early in the season before nitrogen rates are evened out during top-dressing.

Existing yield maps can be fed into a home computer and after the location, soil type, rainfall, previous cropping and organic matter status have been keyed in can be sent via the Internet to a central computer in Germany. This considers the N requirement and nutrient removal, then calculates a ratio for a balanced compound fertiliser to meet average P and K requirement and draws up a variable NPK application map.

Ready in 20secs

In 20 seconds this is back on the farm ready to be downloaded to a chipcard for plugging into the computer control unit on the variable rate spreader or sprayer.

Cost of NPK-Online service, which is due to be fully available next season, has yet to be set.

Later in the spring PrecisioN-Sensor can match top-dressing rate to actual crop need. This is done by a bank of eight sensors on a boom at the front of the variable rate machine which checks the colour of the crop and interprets its N status.

The data is fed to the tractors on-board computer and within four seconds the application rate is adjusted to suit need.

Increased precision should reduce the risk of lodging and disease and improve both yield and grain quality. Trials over four years comparing best fertiliser practice with a variable rate approach have given an average yield boost of 3.3% from using less N. &#42