DJ’s starter fert applicator is the winner of the intermediate category in our Farmers Weekly Inventions Competition 2022.

Derek Howard, known as DJ, of Alton-based contractor Scribeland, built a starter fertiliser applicator to spray liquid nitrogen and phosphorous in the bands of oilseed rape he drills with a 4m Sumo LDS.

His aim was to get more uniform establishment and vigorous early growth to see off the flea beetle threat across the 70ha of rapeseed sown this year and, at the same time, use the fertiliser more efficiently.

The starting point was an old 1,000-litre Knight front spray tank, which he stripped and resprayed to match the chassis of his Fendt 828.

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He then sourced a set of Arag valves to control the filling and liquid transfer to the back of the tractor.

These were mounted behind the main tank frame alongside an old hydraulically powered centrifugal pump, which he rejuvenated with a new impeller.

This took a bit of setting up, as he only needed a modest flow at low pressure – not the high output that the pump was originally designed for.

Regulation of the application rate is managed by an off-the-shelf RDS Spraymaster 200.

This is wired to an in-cab plug that shares the tractor’s data, so is able to alter the application rate according to forward speed and automatically start/stop when the linkage is lowered or lifted.

Half-inch pipe takes the liquid fertiliser to the back of the tractor, where it enters a distribution manifold made from thick-walled water pipe.

Eight small-bore transparent pipes with push-fit joints then take the liquor to home-made toolbar brackets between the legs and roller of the LDS.

These have shields, made from halved steel tube, that protect the Teejet SJ3 fertiliser nozzles, which were selected to give precise coverage and minimal drift in a 165mm-wide band behind each leg.

The nozzles, too, have push-fit connections to their carriers, meaning they can be quickly whipped off in case of a blockage.

To finish, Mr Howard fitted some old Cat belly weights to the tank chassis to help keep the tractor’s front wheels on the ground.

All in, the build cost £3,500.