Put lime at the top of your fertiliser shopping list
Drystock farmers have been encouraged to make spreading lime a priority on their farms this year.
Confirmed by results of soil tests carried out on drystock farms nationally over 2024 and presented in the Teagasc Soil Fertility Report 2024, many soils on drystock farms are lacking a vital ingredient for grass growth – lime.
A dataset of over 42,000 soil sample results, the Teagasc Soil Fertility Report 2024 shows that just 38% of soils have a pH >6.2 – the optimum for grass production on mineral soils - meaning that most will benefit from lime applications to correct soil pH, provided a requirement has been identified through soil testing.
The benefits of bringing soil pH to the optimum were discussed by Mark Plunkett, Teagasc Signpost Programme Training and Development Specialist, when he joined Catherine Egan on a recent episode of the Beef Edge podcast.
Drystock farmers need to invest in lime, Mark Plunkett explained, as liming of acidic mineral soils brings many benefits.
“You can grow about 10-20% more grass and it will increase the availability of nitrogen (N), phosphorus (P) and potassium (K). Through liming acidic soils, we can unlock 30-50kg of N/ha/year, there is a free bag of nitrogen that will be released annually from your soils by getting your pH right.”
Nutrient use efficiency
Along with having benefits in terms of the nutrients released from the soil, Mark Plunkett noted that having soils at optimum levels for soil pH, along with soil P and K indexes, is essential for making the best use of chemical and organic manures applied.
Providing a simple outline of how soil fertility and nitrogen use efficiency (NUE) are interconnected, Mark Plunkett used an example of a farm spreading 100kg/ha of chemical N/ha/year.
Where pH, P and K are suboptimum, he explained, just 35% (35kg/ha of N) will be available for grass growth and the other 65% is lost from the system. Where soil pH is corrected to the optimum, 51% (51kg/ha) of this N is available for grass growth.
Continuing Mark Plunkett said: “If the pH is not right, you will get a poor response from the applied N, P and K, both in bagged fertiliser but also in your valuable cattle slurry and farmyard manure. Lime should be a priority. Getting the pH right should be the first investment on drystock farms.”
“Lime costs €30-35/t and it will fix the problem for the next five years and you will grow more grass,” Mark Plunkett concluded.
For more information on fertiliser planning, the full episode of the Beef Edge podcast is available below: