When planning the farm’s annual fertiliser programme, it is essential to factor in the land’s lime requirements. Correcting soil acidity is the first step in fertiliser planning and goes hand in hand with efficient management of fertiliser and manure applications.
In order to put together a fertiliser plan, farmers should first soil sample the farm to identify the pH and nutrient requirements for specific soils. Soil sampling should take place every 3-5 years in order to correctly monitor pH levels in the soil and ensure that soil pH is maintained in the optimum range for both grassland and tillage crops. Weather permitting, soil test results will enable farmers to plan for targeted lime application at any time of the year.
Grassland – Target soil pH
Lime is an essential ingredient for grass production. Maintaining the optimum soil pH with lime will increase grass production, increase the availability of soil Phosphorus (P) and Potassium (K) and increase the availability of applied NPK.
While lime can be applied throughout the year, towards the end of the first rotation in spring offers a good opportunity for liming as there are often large areas with low grass cover. When fields are being closed off for silage, it is advisable to plan the application of lime after the first cut of silage has been completed. It is best practice to spread lime on bare ground as applying lime to fields intended for silage with heavy grass covers can reduce silage quality if the lime is not washed off the grass by rain. Farmers should also plan to spread lime following the second cut of silage in order to increase grass cover for the final rotations of the year. When planning for the following spring, it is advisable to plan to spread lime prior to cattle going out to grass again, weather permitting.
Achieving return on investment
Similar to any business, it is important to ensure that your farm is achieving a positive return on investment. With careful planning to correct soil pH by using lime, farmers can release up to 80kg N/ha/year. Farmers should aim for a pH of 6.3 on mineral soils and a pH of 5.5 on more peaty soils. By optimising the pH of soils, farmers can increase their annual grass output by up to 1tDM/ha/year, which according to Teagasc is worth €181/tonne of grass dry matter (DM) thereby reducing farm feed bills. According to Teagasc, a dairy farm making a €100 investment in lime will get an annual return of approximately €725 through extra grass production. This represents a return of €7.25 for every €1 invested in lime.
In summary, the key message is that, when planning the farm’s annual fertiliser programme, farmers should plan to apply lime every year to a proportion of the farm based on recent soil analysis thereby ensuring that soil pH is maintained at its optimum level, the availability of soil nutrients is enhanced and grass DM production is maximised.
Finally, to ensure increased consistency in quality, we recommend lime is purchased only from Grolime certified suppliers.
To learn more, visit www.grolime.ie or call your local Grolime certified producer.