Liquid nitrogen (N) has made a comeback in recent years, with a number of merchants now offering the product as well as providing the storage tanks with the package.

Common products include UAN (urea and ammonium nitrate). Some farmers around the country produce their own liquid nitrogen by dissolving urea and sulphate of ammonia using specialised blending kits.

The most common method of application in Ireland is using an existing sprayer fitted with what are called ‘piddle nozzles’ or dribble bars, which deliver the liquid in a stream rather than a spray.

At the recent event in Louth organised by Weldon Agri, growers got a chance to see how liquid N can work using a sprayer on Irish farms. The product offers many advantages but, before making the switch, growers must be aware of the potential disadvantages.

Pros

Accuracy: Applying liquid N through a sprayer allows for exact placement of fertiliser across the entire width of the tramline. Sprayers equipped with GPS section control can limit overlaps on headlands and reduce the risk of lodging.

Storage and handling: Liquid N doesn’t require a building for storage, just a tank which can be rented or bought in most merchants who offer the product. This saves the need for a forklift to handle the bulk product. When filling from the yard, spraying the product only requires the same amount of labour input as a fungicide treatment.

Consistency: With liquid N solutions, the nutrient content is consistent, meaning that each drop contains exactly the same as the next drop.

Flexibility: The product can be applied on conditions which doesn’t suit granular fertiliser. Liquid N can be applied when damp, windy or wet as long as the ground will travel.

Machinery efficiency: The sprayer will be in use when it would otherwise be idle, making better use of the purchase. Increased use of the sprayer will lead to a reduction in use of the fertiliser spreader, saving on wear and tear.

Cons

Corrosion: Liquid N is highly corrosive to pumps, booms, chassis and electrical connectors. The product generally requires a stainless steel boom and, some would argue, a stainless steel tank.

Wear and tear: There will be increased wear and tear on the sprayer. This will shorten its lifespan but this is partially offset by reduced use of the spreader. However, mounted spreaders are generally cheaper than sprayers and there is less corrosion on the machines when spreading granular N.

Scorch: Leaf scorch is possible when sprayed in certain conditions, particularly during hot, dry or windy days.

Mixing: It is not possible to mix chemistry with many liquid N sources because of the nozzles used.

Weight: Liquid fertiliser is a denser product so a mounted sprayer will be heavier than when using standard spray.

Key points

  • Liquid N has become popular in recent years.
  • Its key advantage includes greater accuracy.
  • The product is very corrosive on machinery, however.

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