Now is the time for lime

Stuart Childs highlights the importance of spreading lime to optimize soil pH and improve fertiliser response for increased grass production and reduced fodder costs, alongside guidelines for nitrogen application before the closed season.

There is much talk of fertiliser in recent days with the minister’s decision to leave fertiliser allowances at 2023 levels for 2024. People are enquiring how much more nitrogen can they spread before the closed season for chemical fertiliser kicks in on September 15^th. The extra units while small will be important for people striving to increase fodder stocks and extend the grazing season which will in turn reduce fodder demands. It is extremely important that the full value of these applied nutrients is captured.

Find out how much extra N, P (if you have and allowance) and K you can spread before September 15^th but you should also ask about the cheapest fertiliser of all – LIME. Soil needs to be at a pH of 6.3+ to perform to its optimum. Many if not all farmers in derogation will have a lime spreading requirement so from a regulation point of view, you need to spread but forget the regulation piece, you should be spreading lime anyway! Many people wonder why we ‘harp on’ about soil fertility so much? Good soil fertility ‘unlocks the door’ when it comes to response to fertiliser. pH is the single most important chemical property in soil. As well as improving the response to applied fertilisers, it also increases the availability of soil nutrients such as phosphorus (P) and potassium (K). Liming alone (Figure 1) can increase grass production by 1t DM/ha.

Figure 1. Effect of Lime and P fertiliser on Grass dry matter yield

The same is true of nitrogen and potassium (Figure 2) as well as many other trace elements.

Figure 2. The impact of soil pH on nutrient availability

While the minister has given a stay of execution on the reduction in nitrogen levels for 2024, these will reduce in 2025. Every kg of nitrogen spread in 2025 and beyond needs to work for you. Regular liming will help maximise the return but it has to be spread to work! Improving the response to fertiliser (both chemical and organic) will increase the amount of grass grown which in turn should facilitate a reduction in bought in feed. This is not only good for the pocket but also will help to reduce the farm gate nitrogen surplus which is a key driver of water quality. Improve your fertiliser response by applying lime where needed, now and at every opportunity available over the next few months to correct pH status. It’s the easiest element of soil fertility to correct yet the one that is most often forgotten. Now is the time to correct your lime!