Faster nitrogen uptake by grass and cereal crops, along with greater accuracy around application rates, has seen liquid fertiliser use on livestock and arable farms grow to 35% of total fertiliser sales in Britain.

During an industry event organised by Fane Valley last Thursday, farmers heard speakers outline the pros and cons of using liquid fertiliser over conventional granular products.

“With liquid fertiliser, the nitrogen is already dissolved. When applied to soils, nitrogen uptake is almost instant” said Fane Valley grassland technical specialist, Gary Spence.

“Conventional fertiliser needs 10mm to 20mm of rain to dissolve granules after each application before nutrients get into soils.

Heavy rain can wash those nutrients into water courses, but a dry spell means granules remain undissolved and there will be atmospheric losses,” he added.

Spence also outlined data from Irish research, where silage was grown over a six-week period using 60 units/acre of liquid nitrogen (24% N) and 65 units/acre of granular fertiliser (24-2.5-10).

After the first three weeks, the liquid fertiliser had grown twice as much grass. By week six, grass yields were more or less identical.

“There was 8% less fertiliser used to grow the same quantity of silage with the liquid product. There is less risk with high nitrogen residuals, making it ideal for farmers operating multi-cut systems,” he said.

Product cost

At present, liquid fertiliser comes in at 24% nitrogen plus 7.5% sulphur and currently costs around £340/t.

There are two options available, starting with 1,000 litre IBC containers but there is a minimum order of 6t.

Liquid fertiliser can also be stored in above ground tanks, with 30m3 or 50m3 silo options, although the minimum purchase order is much higher at 28t.

Tanks must be situated on a concrete base with a safety bund to prevent run-off. Tanks can be rented through Fane Valley and are supplied free of charge when purchasing three or more loads annually.

Purchasing a tank outright will cost close to £7,000 for a 30m3 tank, before ground works and concrete bund costs.

Application

Advice for applying liquid fertiliser is straight forward. It can be used in dry conditions and the boom should be kept at least 50cm above the crop to get an even spray.

Droplet size is important and may require different nozzles fitted to sprayers. It should not be used in damp conditions as it can cause scorching of plants.

Read more

Department awaits Commission response on three-crop rule

Can liquid nitrogen save you money?