Agricultural Lime Supplier

Agricultural Lime FAQ

Which factors influence lime quality?

Neutralising value, fineness and reactivity are the three factors which influence lime quality.
Effective economic liming will rely not only upon the quality and suitability of the liming materials but also upon having a soundly managed liming policy. The aim should be to maintain the lime status of the soil on a rotational basis. The cycle of the rotation will depend upon the locality, the type of soil, and the style of management. The rate of lime loss will need to be established from regular soil pH testing. Annual lime losses vary considerably over the British Isles, and a liming rotation cannot be established by guesswork.
The ultimate objective is to maintain the soil for arable crops at pH seven and pH 6.5 for grassland. (Peaty soils should be maintained at pH 6.5 and 6, respectively).

What is the effectiveness of Agricultural Lime?

The effectiveness of agricultural lime is influenced by several key factors: neutralising value, fineness of grinding, reactivity, and the hardness of the parent rock.

Neutralising value

The neutralising value of a liming material is measured as the percentage of calcium oxide equivalent it contains. For instance, a 100 kg liming material with a neutralising value of 52% is equivalent to 52 kg of pure calcium oxide (CaO). This value is determined in laboratory conditions through a chemical reaction with hydrochloric acid and is always reported based on the ‘as received’ sample rather than on a dry matter basis.

Reactivity

A laboratory test known as the “Reactivity Test” is employed to quantify the effectiveness and reaction speed of a liming material. This test helps estimate how the liming material will behave in soil, and the results typically correlate well with outcomes from long-term pot trials. During the Reactivity Test, the liming material is decomposed in hydrochloric acid under stable pH conditions. The amount of acid consumed over a specific time period directly indicates the reaction time of the liming material being analysed. Results from this test are expressed as a percentage, comparing the sample’s speed and efficiency against pure precipitated calcium carbonate.

Fineness of grinding

Applying coarser lime materials generally necessitates a heavier application for optimal effectiveness. When lime is introduced to acid soils, there is a demonstrated correlation between the fineness of the ground material and crop yield responsiveness. Liming materials with particle sizes exceeding 600 microns (0.60 mm, 60 mesh) can significantly reduce effectiveness unless those materials can easily break down. Fineness is less crucial for burnt lime, which disintegrates into a fine powder when reacting with water, and soft, porous chalks that decompose in soil due to frost action or mechanical cultivation.

Which factors influence lime quality?

Three primary factors influence lime quality: neutralising value, fineness, and reactivity. To achieve effective and economical liming, it is essential to consider the quality and suitability of the liming materials and implement a well-managed liming strategy. This strategy should maintain the soil’s lime status rotationally, tailored to the locality, soil type, and management style. Regular soil pH testing is crucial to establish the rate of lime loss since annual losses can vary significantly across different regions. A systematic liming rotation cannot be established without this data.

The ultimate goal is to maintain soil pH levels at 7 for arable crops and at 6.5 for grassland. The recommended pH levels for peaty soils are 6.5 and 6, respectively.