In 2014, 867,000 tonnes of ground limestone was applied on Irish farms, according to Teagasc.
It says lime has a large influence on the availability of soil nutrients and the efficiency of major nutrients applied in either organic (manures) or chemical (fertilisers) forms.
According to Teagasc latests research suggests that only 35% of grassland soils and 40% tillage soils have soil pH at or above target levels.
Teagasc says maintaining soil pH in the optimum range for grassland (pH 6.3) or tillage crops (pH 6.5) is the starting point for nutrient availability in soils throughout the growing season.
For example it says grassland soils maintained at the target pH:
- Will potentially release up to 80 kg N/ha/year.
- Have increased plant availability of both P & K compared to low soil pH levels (<pH 6.0).
Lime Advice – Ground limestone
- Apply lime to soils to achieve the target soil pH based on the lime requirement as per the soil test report.
- Apply Magnesium lime where soil Mg levels are Index 1 or 2.
- Leave seven days between applying urea/slurry application and applying lime afterwards.
- Leave three months between applying lime first and following with urea/slurry application.
- Leave at least three months between liming and silage harvest.
- On high molybdenum (Mo) soils maintain soil pH <6.2 to prevent negative effects on Cu uptake in ruminant animals.
- Don’t exceed 7.5t/ha in a single application and apply balance in year three.
- Ensure ground limestone meets DAFM. Lime Standards as per DAFM Specification (SI 248 of 1978).
- Product must have a Total Neutralising Value greater than 90%.
- All lime products must pass through a 3.35 mm sieve.
- Not less than 35% must pass through a 0.15 mm sieve. (Therefore at least 350kg is very fine, very reactive and will begin to work immediately. The remainder will work in the second and subsequent years).
- The moisture content must be less than 3.0% specification
- Granulated lime is fine lime (i.e. <0.10 mm sieve) and therefore very reactive.
- Apply at a ratio of 3:1 for example where 3t/ac ground limestone is required apply 1 tonne of granulated lime over a 5 year period (1,000 ÷ 5 = 200kg/ac/year).
- Check neutralising value of the granulated lime product (compared with ground limestone)
and adjust the application rate appropriately.
- Granulated lime needs to be applied annually to maintain the soil pH correction.
- Treat granulated liming products like a fertiliser in that they are applied annually.
- Consider costs over the three-four year period when recommending granulated limes.