Can you afford not to spread lime?

Kenny and Geoffrey Malcomson: Lime is essential to make the most efficient use of nutrients and maximise grass growth
Kenny and Geoffrey Malcomson: Lime is essential to make the most efficient use of nutrients and maximise grass growth

Some time you will have heard the expression “To be penny wise and pound foolish”. After a period of low milk prices some dairy farmers may be tempted, with good reason, to limit what additional spends they make on their farms.

The table shows how soil pH affects nutrient availability. Applying lime is one area which may suffer, but rather than asking “Can I afford to spread lime” perhaps you should be asking “Can I afford not to”.

Dairy grassland spread with lime this week on the Malcomson farm

Dairy grassland spread with lime this week on the Malcomson farm

How much lime?

Soil analysis is the starting point in determining the crop nutrient requirements for optimum grass and crop growth. An up to date soil analysis will provide the quantity of lime required to correct soil pH as well as providing information on the Phosphorous (P) and Potassium (K) crop requirements. Only apply lime based on a recent soil analysis. Do not exceed 7.5t/ha (3t/acre) in a single application. If the soil analysis indicates more than this it should be applied over two years and ideally with a soil analysis before the second application.

When to apply?

If little lime has been spread in recent years fields with the largest requirement should be spread first. It can be spread all year round and ideally to either bare ground or ground with low covers of grass on it. Good practise would be to draw up a farm liming plan and apply lime (if required) to 20% of the farm annually. To avoid loss of nitrogen it is recommended to wait at least 10 days after slurry or urea application before applying lime.

Theory in practise

Kenny, Sheila and Geoffrey Malcomson run a herd of 140 Hol/Fr cows at Ringclare outside Newry. The herd produces 8,000 litres/cow/year with 4,000 litres coming off forage. Great emphasis is placed on growing high yields of quality grass for both grazing and silage production. This year, as is regular practise, soil samples were taken off a proportion of the farm with results indicating that soil pH was 5.8. Geoffrey understood that in order to make most efficient use of nutrients this ground required some lime to be applied. Pink lime was duly ordered from Joseph Walls, because of its high Calcium content, and applied this week at a rate of 1t/acre to 34 acres, including land used for grazing dairy cows.

Summary

All of us would like to be able to grow more grass from our land. Perhaps analysing soil and applying lime is the first step to achieving this goal. “Can you afford not to?”