Growers switching to liquid fertiliser are being advised to start planning now for the autumn cropping season.
A wet eight months mean more arable farmers are moving away from solid fertiliser, says Phil Burrell, head of crop nutrition for Yara. Now is a good time to start planning for the 2024-25 cropping year, he adds.
“Large parts of the arable area haven’t been planted with winter cereals, the oilseed rape crop has continued to present challenges – and there are still farmers out there who haven’t got any spring barley drilled.
“It’s been very challenging and it’s inevitably going to lead to fertiliser carryover as we go into the new cropping year. For farmers thinking about fertiliser strategies and moving from solid fertiliser to liquid, now is the time to start planning.”
What to consider
The main difference between liquid and solid fertilisers is that liquids come in solution form rather than solid granules or prills. Beyond these basics, there are other factors to consider when thinking about switching to liquid.
Liquid fertilisers are available in a range of different formulas including nitrogen, nitrogen-sulphur mixtures, and nitrogen-phosphate-potash and sulphur (NPKS) mixtures. Like solid fertilisers, they are applied to the soil.
First, liquid fertilisers are applied with a crop sprayer, so farmers need to consider their sprayer capacity, so they don’t put it under too much pressure. Secondly, fertiliser can be corrosive, so good sprayer hygiene is essential.
Another consideration is the concentration of compound NPKS fertilisers. Nutrients like potassium are water soluble so it is not possible to achieve the same concentration in a liquid as you would in a straight solid fertiliser, such as muriate of potash.
Although there are limitations to using liquids in some farming systems, they can bring improved operational efficiency, says Mr Burrell. Liquids are stored in a tank, so don’t require any shed space, he adds.
“You won’t need to take bags off the lorry, put them in the shed, then bring them back out of the shed and put them in a trailer to take down to the field. Plus, you’ll have no bags to dispose of at the end of it. There are several efficiency savings here.”
Liquid fertiliser can also encourage farmers to upgrade their sprayer and go to a wider tramline to improve output as well as reducing labour costs. If farmers strategically locate their liquid fertiliser tanks, application can be a one-person job.
Preparing to switch
Achieving these benefits requires some preparation.
Before the storage tank arrives, a reinforced concrete base must be put down for it to sit on. The tank should be bunded for best practice, with safe access – such as ladders over the bund – for delivery staff and farm workers.
The location of the tank must also be risk assessed – which a good supplier should be able to assist with. The last thing you want is a tank in the middle of a busy farmyard – it’s a recipe for an accident,” says Mr Burrell.
“Before switching to liquid fertiliser, one of our farm business managers would visit the farm, do a site survey, and make sure it’s away from watercourses, aquifers, pylons, electric poles, and traffic.”
Sprayer nozzles also need to be changed. A conventional crop protection nozzle sprays a fine mist to target the leaf of the weed or plant. Liquid fertilisers use a dribble bar or specific fertiliser nozzle so a steady stream of liquid hits the soil.
“Our team has lots of knowledge on application and can advise on the best type of fertiliser nozzle for your sprayer, whether that be a dribble bar or a singular nozzle with multiple outlets to make sure the liquid goes where needed.”
Liquid fertiliser enables more flexibility with timings. Unlike solid fertiliser, liquid can be applied in the rain – applications can be made even when the weather is changeable. Applying liquids early where possible also minimises scorch risk later in the crop’s life.
Other benefits
Using liquid fertiliser minimises the impact on the environment thanks to the improved accuracy that’s possible. “When we think of the outsides of a field, we don’t want to be putting fertiliser where it’s not needed, particularly into the environment.”
As well as environmental benefits, there are also yield benefits, particularly for farmers with irregular-shaped fields and lots of headlands, says Mr Burrell.
