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Take advantage of weather to spread lime

Now is an ideal time for grassland and tillage farmers to apply Ground Limestone based on soil test results, as weather and soil conditions are good. Mark Plunkett, Soil & Plant Nutrition Specialist outlines the facts.

The Benefits of Liming

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

Lime is a soil conditioner and controls soil acidity by neutralising the acids generated from N fertiliser and slurry applications and following high rainfall. Soil pH has a large influence on soil nutrient availability. Aim to maintain mineral soils in the pH range 6.3 - 7.0 and peat soil in the pH range 5.5 - 5.8 to maximise nutrient supply. Maintain tillage soils in the optimum pH (6.5 to 7.0) range for efficient nutrient availability over the growing season and sufficient crop uptake of plant nutrients.

Return On Investment (ROI) From Ground Limestone Usage

  • Research shows average grass production response of at least 1.0 t/ha and 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 investment in lime equates to approximately €700 in extra grass production annually or approximately €675 in extra crop production annually

How much lime to spread?

  • Test soils on a regular basis (every 3 to 5 years) to determine lime requirements
  • Only apply lime based on a recent soil test report
  • Don’t exceed 7.5t/ha in a single application
  • Application rates >7.5t/ha, apply 50% now & remainder in 2 years

Lime & Slurry /Urea

The type of N supplied in slurry and from urea is ammonical N and is prone to loss if applied to freshly limed soils. To avoid N loss the following is recommended:

Wait at least 3 months after liming before applying Urea or slurry application

Wait 10 days after slurry or urea application before applying lime

You can view the Teagasc Advice on Liming Leaflet for grassland here and view the Advice on Liming for Tillage Crops here