14 June 2002

Better deposition to beat disease range

IMPROVING spray deposition and turning patch spraying theory into practice will be among the leading application developments at Sprays and Sprayers 2002.

Lurmark and host Syngenta, for example, will unveil the "Az nozzle" designed to improve the performance of ear-spray fungicides, while Micron and Lechler will introduce their variable rate application concepts.

The jointly developed Az nozzle addresses the difficulty of getting even coverage of fungicide on to ears of wheat to protect against the complex of diseases that can have a serious impact on grain quality and appearance.

With a normal flat fan tip, up to twice as much spray may be deposited on the side of the ear facing the sprayer during application, with a risk that the "shaded" side may receive too low a dose to provide fully effective disease control. One option is to use a very fine spray, but at todays fast operating speeds, turbulence tends to play havoc with such sprays.

The new nozzle takes advantage of the droplet size control provided by air induction and has an offset outlet to angle the fan backwards a little (about 10í) to counteract the effects of forward speed.

Microns PatchSpray system uses patented electronics software developed in trials at Silsoe Research Institute to control a twin nozzle spray line for automatic variable rate pesticide application.

Two items of hardware are used: The RDS ProSeries 8000 controller, which acts as an interface between GPS-generated weed maps and the sprayer, and a kit that equips new sprayers or converts existing ones with a single spray line carrying duplicate nozzles.

In essence, this gives an on-the-move choice of three application rate bands, with the software ensuring that the best combination of nozzle and pressure is used for the rate required while protecting spray characteristics.

Lechlers Select system uses a multi-body assembly carrying two, three or four nozzles to provide a wide range of application rates through any one nozzle or any combination of all of them.

Variable rate liquid fertiliser application is an obvious candidate, says Amazone, which has adopted the system for its large trailed sprayers, either under manual control or using software developed by Mueller Elektronik for GPS and digital map control.

Other nozzles making their debut include additional AI air induction and XR extended range TeeJet tips from Spraying Systems, plus a one-piece tip and cap nozzle, and the PneuJet XL, a new version of the Sprays International air induction tip. &#42