As part of the Signpost Farms programme being run by Teagasc, a new list of 12 steps has been published, outlining the 12 ways dairy farmers can reduce gaseous emissions from their farm.
In this article, we take a look at each step and address how easy or how difficult it will be to achieve.
Step 1: Use protected urea
This is an easy win in terms of reducing emissions.
The problem with CAN-based nitrogen and compounds containing CAN nitrogen is that they release high amounts of nitrous oxide emissions when they interact with soil.
It is possible to switch away from CAN-based nitrogen altogether and just use protected urea with or without sulphur and potash and get the phosphorus (P) and potash (K) requirements in the form of 0:10:20 or 0:7:30 etc. All it requires is a change of habit.
Step 2: Apply lime
Increasing soil pH to optimum levels makes all other nutrients more available for plant growth and gives a greater response to applied fertiliser. Applying fertiliser on fields with a low or sub-optimal pH is a waste of resources.
Step 3: Build or maintain soil fertility
The guidelines state that P and K fertiliser such as 18:6:12 should continue to be spread. While 18:6:12 is a very useful fertiliser and has served farmers well, the nitrogen portion is CAN and meeting the emissions targets means moving away from CAN altogether.
That said, the principle is sound and is easy to implement provided the farmer has a P allowance.
Step 4: Use 100% LESS slurry
The use of low-emission slurry spreading (LESS) equipment is a no-brainer for all farms.
It reduces ammonia losses and thereby makes the nitrogen in slurry more available for plant uptake.
This then reduces the amount of chemical fertiliser required, saving costs and reducing nitrous oxide emissions.
The other big advantage of LESS is that it enables farmers to apply slurry on fields with higher grass covers, without soiling the grass.
The only downside is that there can’t be any foreign objects in the slurry or it’ll clog the pipes in the spreader.
Step 5: Reduce chemical N by 10kg/ha
For a farm spreading 250kg N/ha, reducing chemical nitrogen use by 10% is a 4% reduction and should be easy enough to achieve by making more use of clover, LESS and lime. However, for a farm applying 100kg N/ha and already implementing the aforementioned measures, a 10kg N/ha reduction is 10% less chemical nitrogen.
That will probably equate to 300kg less grass grown per hectare. If this feed is to be replaced by something else which costs more, it would make more economic and environmental sense to spread the nitrogen.
Steps 6, 7, 8 and 9
These steps have all got to do with improving technical performance such as better grassland management, improving animal health, improving dairy herd quality and increasing milk solids per cow.
While improving profitability, each of these measures will also help to reduce the carbon footprint of dairy farming in Ireland. There’s nothing new or exciting in any of these steps and farmers have been encouraged to take them up for decades.
Actions such as measuring grass, using a herd health plan, milk recording and culling poor performers are all tried and tested recipes for success, but unfortunately not enough farmers are practising them. If the existing methods of advising farmers haven’t encouraged sufficient change up to now, how are Teagasc and others going to convince farmers to take them up in order to reduce emissions?
Step 10: Reduce age at first calving
Last year, 74% of all dairy heifers calved at between 22 and 26 months of age, which is a big improvement on the 2012 figure of 59%. However, it still shows scope for improvement.
The main reason a heifer may not calve inside this window is if she is not bred because the farmer thinks she’s too small, or if she didn’t go in calf and is recycled for the next season.
Calving outside of the 22 to 26 months of age window means the heifers are contributing to methane emissions, but not delivering any product for it ie reducing efficiency. This can be avoided by making sure youngstock hit target weights and culling empty heifers.
Step 11: Finish cattle earlier.
A bit like calving heifers at two years of age, earlier finishing of cattle reduces the amount of time they are hanging around on farms and contributing to methane emissions.
Genetics has a huge part to play here, as has management and what system is chosen. For example, keeping males as bulls leads to faster finishing times at higher liveweights than bullocks. Using high dairy beef index (DBI) bulls will also lead to faster finishing times for heifers and steers.
Step 12: Incorporate clover
Teagasc states that sowing 2kg of clover per acre will replace 100kg N/ha per year. If only it were so simple. Clover is difficult to get established in existing swards and is also difficult to retain in swards when it is established. There is no doubt about its ability to fix nitrogen however.
There’s not one measure contained here that doesn’t give a financial return as well as reduce emissions. But as we know, not all farmers are motivated by extra money in order to do something.
If the current model of advisory and extension hasn’t worked to get more farmers on board up to now, is there a plan to introduce a new model in order to reduce emissions at farm level? There needs to be a five-year plan for making the change happen.