Case Study: North Devon growers, David Down & Steve May near Barnstaple
Agronomy+ helps two growers make the most of liquid fertilisation
Liquid fertilisation is becoming increasingly popular with West Country farmers keen to achieve the greatest precision in their crop nutrition, flexibility in their field operations and efficiency in their materials handling, not to mention environmental resilience.
Over the past five years, indeed, Devon & Somerset–based agronomist, Mark Smyth has seen the number of growers using liquid fertilisers in place of bagged nitrogen and sulphur more than triple. Rather than replacing their old spreaders, he is finding more and more farms switching to their sprayers for the bulk of non-P&K fertiliser application.
“This makes sense in so many ways,” Mark explained. “The accuracy of application is far higher with liquids through dribble bars or fertiliser nozzles than it is with prills through even the most sophisticated spinning disc systems. This means you can be sure of applying full fertiliser rates right up to the edge of your crops without the risk of putting too much into your hedge base to feed the likes of brome and cleavers.
“Liquid fertilisers also allow you to work in far more unsettled weather. They’re almost immediately available to your crops even in dry conditions when prills can lie on the surface for so long. They are much easier and less labour-intensive to handle than bags. And they’re proving especially cost-effective.
“More than enough wet and windy days always seem to get in the way of early season spreading here,” pointed out Mark. “With the relatively small, uneven-shaped fields we have too, the outside 8m or so of the headland bout where the accuracy of spinners really falls off – even with deflector vanes – can be a large proportion of the cropped area.
“As well as being more achievable with liquids, accurate application is more essential to minimise lodging risk. Windy weather in May and leaving less than three days after chemical spraying may cause unsightly cereal scorching. And good sprayer hygiene is vital to prevent equipment corrosion. But these are the only real watch-outs.
“So it isn’t surprising liquid fertilisation is catching-on in a big way where farms have more than 200 ha of cropping. All the more so given the quality and consistency of modern formulations and the practicality and flexibility of today’s self-propelled sprayers.
At Hayne Farm, Bishops Tawton near Barnstaple, David Down has relied on liquid fertilisers, for a good 20 years across an owned, rented and share-farmed business now extending to around 1000 ha of crops and grass.
David currently runs two 24m Bateman self-propelled sprayers for the bulk of his fertilisation as well as all his crop protection work. For maximum operational capacity and flexibility, these are serviced from 290,000 litres of farm storage by 10,000 litre and 12,000 litre stainless steel bowsers developed from old milk tankers.
Apart from a small amount of straight N for some of his Taw Valley Contractors’ sheep farming customers, he and Mark base their fertilisation on two primary liquid mixes – higher N and lower sulphur inclusion for cereals (5 to 1) and a relatively lower N and higher S product for oilseed rape.(1.6 to 1).
“Precision is the main reason we use liquids,” stressed David. “To get the most from our crops we need the most accurate and timely nutrition. This is something we can’t get with solids because of the large amount of headland work we always have, the slopes we have to work on, and the very changeable weather we have to work with.
“A while back we tried liquids for the headlands of 30 ha of one farm and when we’d finished found we’d done half the entire area! This shows how much of our cropping is at risk from the serious drop-off in solid applications you get at the field edges if you want to avoid fertilising the hedges. Yet it’s these edges we must fertilise right if we’re to achieve the 10t/ha wheat yields we’re after.”
Aided by GPS accuracy in drilling and setting-up tramlines, Accu-Rate dribble bars sectioned-off to give a constant flow across slopes and a purge system to supply the liquid evenly to all bars at start-up, David Down’s liquid system delivers an enviable consistency of application to the edges of every crop.
At the same time, it gives him the ability to keep fertilising accurately in showery weather and the flexibility to chop and change between spraying and fertilising – through the day, if necessary – depending on the weather.
“This and the availability of the fertiliser almost as soon it’s applied means we can feed our crops exactly when they need feeding, almost regardless of the weather,” David stressed.
“Today’s liquids are very different from those we had in the old days,” he added. “Their quality is excellent, and we’re always able to get extra loads whenever we need them. Using the tank fill and spring fill options to secure the supplies we need at prices agreed ahead of the season is valuable too. As is the fact that we only pay for any spring fills we actually take, so we don’t have to finance unnecessary carry-over stocks.
“The whole system works really well for us. We’d never switch back to solids even if we could rely on them being a lot cheaper, which they certainly aren’t. Quite apart from everything else, we’re saving a lot of man-hours and shed storage space, both of which we’re putting to much better use.”
A Fresh Approach
Across the Taw Valley at Newton Tracey, Steve May is only just starting out with liquid fertilisation at New Cross Farm, having had two 50,000 Agrii GRP tanks installed before Christmas. Running the 260 ha arable and 150-cow beef rearing business single-handed, labour-saving is an important priority for him alongside continual productivity improvement.
In pushing wheat yields to their target of 10+t/ha, he and Mark Smyth have been keen to do everything possible to improve the precision of their fertilisation. With an average field size of around 6ha, this has meant particular attention to headland applications.
“Our 24m twin-disc Lely Centerliner was one of the best spreaders on the market when we bought it 15 years ago and we’d never been unhappy with the job it did,” recalled Steve. “But, we’d always had to dodge round the weather to get our spring fertilisers on.
“As we already had a 24m Bateman sprayer, when we started thinking about replacing the spreader we looked into the liquid route. What really swung it for us was seeing the system working so well on the Somerset iFarm. We really liked the accuracy it gave, working right up to the crop edges, and the fact that applications weren’t nearly so weather-dependent.
“So we invested in a 9000 litre bowser, three sets of liquid fertiliser nozzles and a concrete pad for the tanks. At less than £10,000 this compared very favourably with the cost of a new spreader.”
For simplicity and to enable them to take more of their annual needs at the more economic early tank fill rate, Steve and Mark went for a single Omex grade rather than different mixes for their cereals and OSR. At 26%N, 5% S03, Nitroflo-S works well for both crops, with extra sulphur applied to the rape early as polysulphate using the old spreader – also employed for P&K applications.
Having completed his first liquid applications this season, Steve May is very pleased with the way everything has been working. Although he thought liquid application would take longer than spreading, the slower forward speed has been balanced by far less re-loading time. What’s more, he’s been able to spray under conditions he would never have dared spread in.
“There’s no problem if it rains now,” he said. “I still get the same even application. I can safely leave the bowser in the field overnight if I need to. And I can easily switch from chemical spraying to fertilisation if conditions deteriorate. This is great for our timeliness and workloads.
“Unlike spreading, we know we’re getting 100% accuracy right up to the crop edges. We know this because any misses become brutally obvious in crop growth within the week. We’d never see any striping with solids, mainly because it only becomes visible with a spreader variation of more than 20%.
“As well as cutting down on wastage by putting our fertiliser where it will do us most good, keeping it strictly confined to the crop is a big plus environmentally,” Steve May noted.
“The system is also giving us far more flexibility in our OSR fertilisation. Mark and I find a mid-flowering nitrogen application really valuable in supporting pod fill rather than canopy growth. Unlike spreading, the height of our rape now doesn’t get in the way of applying.
“Liquid fertilisation has also been working well for our spring cereal seedbeds. And we’re looking to use it for our grass aftermaths where it should be especially useful in kick-starting re-growths in dry weather. It’s early days yet, but I’m definitely a convert.”