Spray water rate use on farm

You know how it goes. You are entirely focused on harvest then before you know it you are back on the sprayer seemingly playing catch-up applying pest and weed control programmes hoping the sprayer is in good fettle for the upcoming season.

But taking time to look back over last year’s spray programme, was there anything you would do different or better?

Looking at water rates, are you ‘eeking out’ a tank full to cover a certain area of land or are you taking a more proactive approach to ensure that expensive chemical does the best job it can for you?

AHDB York Monitor Farm David Blacker has taken the latter course of action and raised water rates 280lt/ha for all soil acting pre-emergence herbicide applications and applying it through fore and aft facing twin cap nozzles.

“I don’t have resistant black-grass here yet and don’t want it,” said David. “So I use higher water rates and do it right.” David uses two 04 flat fan nozzles at 3 bar pressure and keeps the speed to 8 to 10 kph spaced at 50cm to produce a medium spray quality.

“I know I can go faster but if there’s an extra 5% control available by using higher water rates, twin-cap nozzles and a lower speed then I’m going to take it” he said.

“I realise some operators aim for a 1000 acres in a day, but I prioritise chemical efficacy rather machine efficiency” David concludes.

Using a bowser may also be necessary. It cuts non spraying time down and can raise your sprayer output by nearly 50% without cutting rates. It seems like a waste having a man running around after the sprayer but has a dramatic effect on the sprayer’s capability.

David’s twin cap nozzles in action applying 280litres per hectare

close up of twin cap nozzle on David’s sprayer

Above top: David’s twin cap nozzles in action applying 280litres per hectare

Above bottom: close up of twin cap nozzle on David’s sprayer. Both photos; David Blacker.

If you’re looking at a new sprayer altogether there’s no end of choice, from new or specialist second-hand dealers, what you have to ask yourself in these low commodity price and politically new era do you really need to self-propelled (which were first sold as having a light foot print) or would a trailed machine work? You can access the same amount of technology, enjoy at least the same output, they can be quicker on-road between jobs and are about half the price to buy against a self-propelled.

Through the AHDB’s CropBench+ service trailed sprayers with tractor included show a £4/ha saving, and you make better use of your drill tractor too. Sure, there’s the old arguments about crop clearance under your tractor when desiccating oilseed rape but are you losing that much crop to justify a high-clearance self-propelled? And the old chestnut about stability on slopes, well it’s time to leave the 72 inch wheel track of father’s day and go to 80 or 84 inch wheel track, it helps!  Of course you are free to buy what you like, it’s your business. But high capacity machinery that goes under used place a high burden on profits, or indeed makes losses very difficult get under control.



Based at Ashkam Bryan near York, Harry grew up on a beef farm in his native north Wales. Subsequently, Harry developed an interest in farm machinery that took him around the world working in agriculture. Having managed a plant breeding farm near Cambridge for Monsanto, in 2005 Harry joined John Deere as Crop Systems Specialist, from where he was recruited by AHDB Cereals & Oilseeds.

Comments are closed here.