Lime Advice for Grassland

1. Lime Advice for Grassland Mark Plunkett, Teagasc, Johnstown Castle

2. Presentation Notes • This presentation can be used for either drystock or dairy training groups as there is double slides for either group. • For example slides 4 & 5, 9 & 10, 13 & 14 are double slides and to be used for either a diary or drystock group during training

3. Annual Lime Applications

4. Soil pH - Drystock Soil pH for Grassland Soils • 68% < pH 6.2 • Lime is essential • Target pH 6.3 • 42,650 soil samples

5. Soil pH - Dairy Soil pH for Grassland Soils • 57% < pH 6.2 • Lime is essential • Target pH 6.3 • 16,750 soil samples

6. Step 2 - Soil pH & Lime Advice

7. Benefits of Liming pH 5.0 pH 6.3

8. Nfertiliser 100 kg=180-220 kg lime How is lime lost from soils? 1 bullock 25 kg of Lime 1,000 L milk 3kg of lime 5 t/ha silage DM 75 kg of Lime Offtake 1 ha Beef - Grassland Example 150 kg/ha N – 300 kg 2 bullocks – 50 kg Lime loss in drainage – 250-625 kg Total lime required – 600 – 975 kg/ha/yr 1-2 ton/acre every 5 years Up to 250-625 kg/ha/yr of lime in drainage

9. Nfertiliser 100 kg=180-220 kg lime How is lime lost from soils? 1 bullock 25 kg of Lime 1,000 L milk 3kg of lime 5 t/ha silage DM 75 kg of Lime Offtake 1 ha Dairy - Grassland Example 250 kg/ha N – 500 kg 2bullocks – 50 kg 15,000 L Milk – 45kg Lime loss in drainage – 250-625 kg Total lime required – 845 – 1220 kg/ha/yr 1-2.5 ton/acre every 5 years Up to 250-625 kg/ha/yr of lime in drainage

10. Effect of soil pH on soil P availability Soil P level (mg/L) Soil pH Data points represent the 35 fields on one farm (Doonbeg)

11. Why Lime Soils? • Increases nutrient availability • Soil N release • 80kgN/ha/year (2 bags CAN/ac) • Increases soil P availability • To move 1 P Index (€300-400/ha) • Lime before building soil P • Target pH 6.3-6.5 Sheil et al, 2013

12. How Much Extra Grass Produced? Dairy €180 ROI €7:1

13. Return on Investment from Lime Farm example • Heavy clay mineral & peat soils • Soil pH from 5.5 to 6.3 over 5 years across the whole farm • Extra 1.0t DM/ha/yr(valued at €105 or €180/ha) • Average 5.0 t/ha/yr(Costing €25/ha/year) • Return on investment of €4 -7 in extra grass for every €1 in lime

14. Lime sources • Ground Limestone • Finely ground to react with soils • 2. Magnesium Limestone Higher neutralising value /slower to react / Use on Mg deficiency soils • 3. Granulated Liming Products • Reacts very fast / Similar to Fertilisers / Seasonal soil pH regulation

15. Lime Standards • Statutory Regulations – Min Standards for Agricultural Lime • All producers are certified with DAFF • Total Neutralising Value (TNV >90%) • All product pass through 3.35mm sieve • Not less than 35% pass through a 150 µm sieve • Moisture content less than 3.0%

16. Ground Limestone • Most effective • Apply based on Soil Test • Application rate based on soil pH • Most Cost effective • Speed of Actively • Quality • Fine lime work faster (35%) <0.15mm • Coarse lime work over time (65%) <3.35mm

17. Granulated Lime Products • Finely ground limestone (<150 microns) • No. of Products on the market • 6.5 times more expensive • Granular Product • 100% plant available • Lower application rates • Fast acting to reduce soil acidity • Higher reactivity • Uses • Top Up where pH corrected • Lime Deficiency • Con-acre????

18. Liming Grassland – Rates • Rates • Depends on soil pH • Depends on SMP pH • Max single App. 7.5t/ha • >7.5t/ha • Apply 50% now • Remainder in 2 years • Avoid high rates as they will:- • Reduce Major nutrients (esp. P) • Reduce minor nutrients (Mn, Cu, Zn & B)

19. Make best use of all windows of App. • Grassland • Late autumn • Wash in over winter period • Early springtime • Low grass covers • After 1st / 2nd cut silage • Reseeding time apply during seedbed preparation • Wet soils / heavy equipment – Weather • Soil type / organic top – Clare • Little & often approach

20. Managing lime on high Mo soils • Factors – Mo in herbage increased by: • Increased pH (>6.2) • Poor drainage (or wet weather) • Species: Clover > Yorkshire fog > Meadow grass > Fescue > Timothy • Low Nitrogen inputs • (Higher N  higher yields  Dilution of Mo in herbage + less clover)

21. Managing lime on high Mo soils • Soil poor indicator of herbage Mo – Test Herbage (Spring & Autumn) • How high is high? • Mo in herbage > 2 mg/kg DM • High Mo advice is very crude • Indicator of some history in area • Over write as required - local knowledge & experience • 5 t/ha reduction is crude • e.g. soil sample: pH = 5.7 & LR = 4t/ha  reduce application but not eliminate? Remember aim for pH 6.1/6.2 on these soils

22. In Summary • Sample every 5 years • Prepare farm lime plan • Ground limestone most effective • 20% of farm annually • Spread costs / Finance / Budget • Reduce Mo problems if present (- 5t/ha) • Take all opportunities to apply lime • Maintain soil pH 6.3 – 6.5 on mineral and pH 5.5 on peaty soils