Lime is most effective when it is spread in late autumn or early spring, as it will encourage grass growth in the spring time.
So now is an ideal time to think about putting out some lime, if the pH of your soil needs to be corrected. The target pH for grassland soils is 6.5.
As a soil conditioner, lime controls soil acidity by neutralising the acids generated from nitrogen (N) fertiliser and slurry applications and following high rainfall.
Nutrient availability is heavily reliant on soil pH, so maintaining a correct soil pH will increase both environmental and economic sustainability.
There are many benefits to spreading lime. It can lead to an increase in the production of grass and crop yields annually, release of up to 80kg N/ha/year in grassland, as well as make phosphorous (P) and potassium (K) more available. It can also increase the response to freshly applied N, P and K.
In terms of the return on investment from lime, research from Teagasc has shown average grass production response of at least 1t/ha and average cereal grain production response of at least 1.5t/ha from lime alone.
How much lime should you spread?
Soils should be tested every three to five years to determine the lime requirements and should be spread based on an up-to-date soil report.
When applying lime, you should not spread any more than 7.5t/ha. It is recommended that 50% be applied now and the remainder in two years.
Farmers should also be aware that 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, farmers should wait at least three months after liming to apply urea or slurry. They should also wait 10 days after slurry or urea application before applying lime.