Lime

By Marion Fox, B&T Drystock Adviser, Teagasc Galway/Clare

Farmers may not be aware of the National Liming Programme 2023. This programme has been introduced by the Department of Agriculture Food and the Marine to encourage the use of Lime on farms, which corrects soil acidity by neutralising the acids that are present in the soil. Research carried out by Teagasc shows that Liming not only increases soil microbial activity but can also unlock soil phosphorous (P) and potassium (K). Estimates also show that soils with the correct pH will release up to 80kg of N/ha/yr.

The Programme will be open for applications from the 15th March to 20th April 2023. Claims for payment must be submitted by 31st October 2023. The minimum amount is 10 tonne and the maximum is 200 tonnes at rate of €16/tonnes. Farmers who have submitted a Basic Payment Scheme (BPS) application in 2022 and/or a Basic Income Support for Sustainability (BISS) application in 2023 are eligible to apply.

The application of lime has an influence on the availability of stored nutrients in the soil. The optimum pH of soil for grassland is pH 6.3. The target is to have soil at the optimum pH in order to optimise soil fertility. If the lime requirement is greater than 7.5 t/ha or 3 t/ac, it should be split into 2 dressings in year 1 and year 2. Some farmers may choose to apply granulated lime as compared to ground lime, it is more expensive, but has a quicker response and should be treated as a fertiliser; it also needs to be applied each year. But for this scheme it is only applicable to Ground lime.  If the soil is not at the correct pH you will waste money on fertiliser. When the soils are acidic and there is a lime requirement; chemical and organic fertiliser won’t perform to the maximum. If soils require lime the availability of the essential nutrients are reduced as they are bound to the clay particles in the acidic soil, therefore, it is important to optimise the soil pH as this will increase the availability of soil N, P and K.

Maintaining optimum soil fertility increases the efficiency of applied N from 35% on low fertility fields to 63% on fields with an optimum pH, P and K.

Once fields have been grazed-off and grass covers are low, it is an ideal time to apply lime. Identify blocks of land that require lime, for example this could require ordering a load of lime (20t) after each grazing rotation to correct soil pH. Aim to avoid high grass covers > 600kg DM/ha.

The benefits of Lime are as follows

• Increase grass production and crop yields annually
• Release up to 80 kg of N/h/year in grassland
• Unlock soil phosphorus (P) and Potassium (K)
• Increase the response to freshly applied N, P

What are the returns from applying lime?

• Research shows average grass production response of at least 1.0 t/ha and an average cereal grain production response of at least 1.5 t/ha from lime alone.
• This is worth €181/tonne of grass dry matter (DM)or €225/ha of extra grain (15% DM) assuming grain price of €150/t)
• Return on investment – Maintenance lime application costing €25/ha/yr enabling the production of at least €181/ha/yr of extra grass.
• Return on investment – Maintenance lime application costing €33/ha/yr enabling the production of at least €225/ha/yr of extra grain.
• At farm level every €100 invested in lime equates to approximately €700 in extra grass annually or approximately €675 in extra crop production annually.

Cattle Slurry and Lime

Spreading cattle slurry on fields that have received lime recently or freshly limed land where the lime has not had sufficient time or rainfall to be washed into the soil, can result in a loss of up to 50% of the available slurry N. To minimise these N losses from slurry apply cattle slurry first and then apply the lime 7 to 10 days later.

Lime and Urea

 For urea, a similar situation to cattle slurry where increased N loss (ammonia-N volatilisation) may occur where straight urea fertiliser is applied on recently limed land. Therefore, apply urea first and apply the lime 7 to 10 days later to reduce the risk of N losses. However, where protected urea is being applied, early trial work indicates that it is safe to apply protected urea to fields that have been limed recently

Lime on Silage Ground

Leave sufficient time (up to 3 months in dry weather) between applying lime and closing for grass silage for the lime to be fully washed into the soil. If lime is transported to the silage clamp or picked up in the baled silage, it may affect good preservation conditions for the silage (acidic conditions), that is if there is a lime requirement on silage ground.

I would encourage all farmers to apply for this scheme as is of significant benefit to your soil fertility on your farm. The closing ate date is the 20^th of April.  Ground limestone can only be applied in accordance with the lime requirement stated on up-to-date soil analysis reports (maximum of 4 years old from date of purchasing the lime).