Understanding Soil pH

Soil pH is a measure of acidity and alkalinity. The nature pH of soil depends on the material from which it was developed. Scottish soils range from about pH 4 (very acid), when most crops fail, to about pH 8 for soils naturally rich in calcium or magnesium.

Soils will naturally tend to acidify due to natural processes (e.g. rainfall, crop growth and leaching in drainage water) and some farming practices (e.g. use of some nitrogen fertilisers). Acidifying processes can cause soil pH to fall quite quickly, particularly in sandy soils, and regular pH checks every 4-5 years are required.

Acidic Soils could be affecting production on many Scottish farms - nearly half of the soil samples collected from our Soil & Nutrient Network farms are suffering from low pH levels. Use the link to download and read a copy of "A Report on Soil and Organic Materials Analysis from the Soil and Nutrient Network Farms 2016 – 2018".

pH Woodland Trials at SRUC Craibstone Case Study

Management of soil pH is a crucial part of a successful cropping system. pH has a huge impact on nutrient availability and mineralisation of organic matter through microbial processes, both of which impact on crop growth and yield, rooting behaviour, production of biomass residues and consequently soil organic matter. The Woodlands pH Rotation, located at SRUC Aberdeen (Craibstone) which was started in 1961 is an excellent demonstration of this. Read more >>

Soil Liming - Why It's Important

Soil pH can have a huge effect on you soil's productivity. If your soil is too acidic then you can raise the pH by adding lime. In this video, Janette Sutherland, an agricultural consultant, talks us through soil liming. Watch here >>

Liming - An Island Perspective

The soil on your croft is a vital resource and one that can often be neglected. Soil & drainage expert, Gavin Elrick was a guest speaker at an event on South Uist. In this video, he gives us his key recommendations about managing soil pH from an island perspective. Watch here >>

Lewis Grasslands - Liming

A number of materials can be used for liming, the most common being ground limestone. However, other materials such as shell sand are used for liming on the Western Isles. The ability of a liming material to counteract soil acidity is determined by their neutralising value. The speed at which they work is normally dependent on the particle size of the material; a fine powder liming product will work more quickly in raising soil pH than a larger, granular material. Most agricultural liming products, including shell sand, are based on calcium or magnesium carbonate compounds. It is worth noting that it is carbonate that neutralises the soil acidity; calcium sulphate or magnesium sulphate have virtually no effect on soil acidity. Watch here >>

Liming and Biodiversity with RSPB

Did you know that soil liming can not only help your land become fertile but will also help with biodiversity? Improved biodiversity will also help attract more birds to your land which will help to tack pests like leatherjackets. We made this video in conjunction with RSPB Scotland to look at how liming is a win all round. Watch here >>