17 October 2022

First Steps to Reducing Emissions from All Farms – Reducing Our Reliance on Chemical Nitrogen

Farmers are being asked to reduce greenhouse gas emissions by 25% by 2030. But it can be difficult to know where to start with emissions coming from multiple sources on the farm. Siobhan Kavanagh, Teagasc Signpost Programme Communications and Engagement Specialist, takes us through the first step.

Methane is one of the biggest sources of emissions on the farm and is belched out by cattle and sheep.  Nitrous oxide gas comes from fertiliser spreading as well as the storage and spreading of slurry and FYM.  And diesel and energy generation is a source of carbon dioxide.

Step one on any farm should be to reduce the reliance on chemical nitrogen in grassland and cropping systems, hence reducing nitrous oxide emissions.

So how do we do that? 

There are 2 basic steps to doing this:

1. Reduce chemical N use the farm – aim for a reduction of 20% in chemical N use on your farm whether that be a dairy farm using 220 kg N or a beef farm using 60 kg N, the same reduction applies, no matter where your starting point lies.
2. Replace CAN and straight urea with protected urea

How to reduce chemical N use?

So how do you reduce chemical N use without impacting grass or crop growth and consequently farm productivity.  There are 3 steps:

1. Use your soil analysis results to identify fields that need liming to raise pH or improve P or K indexes. Lime is the cheapest nutrient you will apply and can release up to 80 kg N / ha. Too often soil samples are taken for regulatory purposes but not used to make management decisions on the farm. Now is the time to start looking at your soil analysis to help you plan for reducing chemical nitrogen use.
2. Make best use of the valuable slurry on your farm.

• Get it analysed so that you know how much nutrient is in it and where best to use it. There is significant variation in slurry analysis which will impact where and when you use it
• Apply slurry in Spring between Feb and May when you will maximise the value of the slurry
• Use low emissions slurry spreading equipment (LESS) equipment to apply slurry
• Applying slurry in Spring using LESS will triple the N availability in the slurry compared to spreading it later in the year using splash plate.

Replacing CAN with protected urea?

• Its cheaper, right now its up to 40% cheaper than CAN
• It grows the same amount of grass as CAN and this has been seen in multiple studies over multiple sites
• Its flexible, in that it can be used in Spring , summer and early autumn within the permitted spreading periods
• It reduces nitrous oxide emissions by 70% compared to CAN

So it’s a win win – better for your pocket and better for the environment

The 4 R’s to reducing our reliance on chemical N:

1. Reduce chemical N use by 20% on your farm
2. Replace CAN with protected urea
3. Recycle and make best use of slurry on the farm
4. Reward – all these actions are a win win, good for your pocket and good for the environment

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