AHDB has advised farmers that there is greater financial payback from liming as fertiliser prices reach record high levels.
The body stated that liming grassland this autumn could offer “greater financial benefits than usual”.
As part of its grass campaign, consultant Dr George Fisher has urged growers to check soil pH, and if it falls short of the optimum, to apply lime between now and Christmas.
The price of ammonium nitrate has doubled since the beginning of the year, and it has been quoted at £475-£480/tonne for October/November.
In contrast, the price of lime remains relatively stable, providing what the body views as an even better return on investment than in previous years.
Optimising a soil’s pH will ensure its nutrients are available to the growing crop rather than lost through leaching or locked up in an inaccessible form. This has environmental and financial benefits.
Raising the soil’s pH to its optimum by liming will not only increase its ability to release nutrients to the growing crop, but will also optimise conditions for the soil’s biology and health.
This results in less wastage of expensive nutrients, less pollution into watercourses and an improved soil structure, with all its associated benefits.
Long-standing research shows that grass yields can be 30-40% lower as pH drops from the optimum 6.5 down to 5.5.
Optimising soil pH
Further gains from optimising pH include the more efficient capture of nitrogen by legumes, while a growing body of evidence is beginning to suggest soils with a low or high pH can lose more carbon.
All of this points towards the importance of measuring the pH of all grassland soils and optimising pH at close to 6.5.
“This ensures that all nutrients, whether from the soil or a bag or from livestock, are at the optimum availability for the plant to take up, provided everything else is in place,” said Dr Fisher.
“It does not matter when you lime if ground conditions are suitable. However, if you do it now, at the end of the grazing season, it has the winter to work its way into the soil and positively impact the pH next season.”
Once you know the pH, you can obtain the amount of lime your land requires from the Agricultural Lime Association’s website.
Here you will find a lime calculator, which will specify the tonnage you should apply to different soil types. You can also find information about a choice of products.
Soil health is about:
- Chemistry (its nutrients);
- Physics (its structure);
- Biology (its microbial life).
Dr Fisher said: “You can work away on the physics and biology. However, if you don’t have the pH right, you will still lose nutrients.”
“But get them all right, and you reduce your chances of nutrient loss, leaching and pollution and increase your chances of a healthy and high-yielding crop.”