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Natural liming

The principal UK deposits of Calcium Carbonate (CaCo3) Natural Agricultural Lime products are:

Limestone CaCo3 – a sedimentary rock, which is more compacted and denser than Chalk, it is formed from the remains of microscopic foraminifera. Typical Limestone Neutralising Values, dependant on the geological strata, vary between 50 - 55N.V.

Magnesium Limestone CaMg(Co3)2 – formed in the same way as Limestone, but the sedimentation process occurs in the presence of magnesium resulting in a dolomitisation process. Thus Magnesium Limestone typically contains both Calcium (CaCo3 - 42%) and Magnesium (MgCo3 - 53%) carbonates. Typical Neutralising Values are 56%NV.

Chalk CaCo3 - a less densely compacted and geologically younger sedimentary rock predominantly composed of compacted coccoliths (Sea Algae). As a 'softer' rock chalk is more readily broken down and absorbed into the soil solution. Typical Neutralising Values vary between 48 – 54% NV.

Full specifications of all three products in either their natural or Calcined (Burnt) are listed in the 1991 Fertiliser Regulations .

All ALA Members supply Agricultural Lime products in accordance with the current Fertiliser Regulations and the 'Statutory Statement' is provided to the initial purchaser. Quarry produced materials can be sold under a number of permitted names (the term 'Agricultural Lime' is insufficient), each name has a precise meaning and associated declarations, which are required by law.

Farmers should ensure such information is available to them at the time of delivery (as required by law) and that the lime quality is clearly identified at the time of quotation.

pH optimises fertiliser effectiveness

All ALA members supply agricultural lime in accordance with the current Fertiliser Regulations and the 'Statutory Statement' is provided to the initial purchaser.

The UK has a good spread of deposits of natural chalk and limestone suitable for this purpose, though Scotland is short of limestone and relies on imports to a large extent from the North of England.

The Fertiliser Regulations control the sale of agricultural liming materials. Quarry-produced materials can be sold under a number of permitted names (the term 'Agricultural Lime' alone is insufficient), each name has a precise meaning and associated declarations, which are required by law.

Farmers should ensure that such information is available to them at the time of delivery (as required by law) and that the lime quality is clearly identified at the time of quotation.

Materials produced for agricultural liming must comply with the Fertiliser Regulations. Many production sites will hold accreditations for Environmental Management Systems.

The fertiliser regulations and lime

Name, meaning and required declarations of some quarry produced liming materials to comply with the current fertiliser regulations.

Name ofMaterial Meaning Declarations
See Note below
Ground limestone Sedimentary rock consisting largely of calcium carbonate and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 95% will pass through a sieve of 3.35mm and not less than 40% will pass through a 150 micron sieve Neutralising value

Any amount of material as a percentage by weight that will pass through a 150 micron sieve

Screened limestone Sedimentary rock consisting largely of calcium carbonate and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 95% will pass through a sieve of 3.35 mm and not less than 20% will pass through a 150 micron sieve Neutralising value

Any amount of material as a percentage by weight that will pass through a 150 micron sieve

Limestone dust
Coarse screened limestone Sedimentary rock consisting largely of calcium carbonate and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 90% will pass through a sieve of 3.35 mm and not less than 15% will pass through a 150 micron sieve Neutralising value

Amount of material as a percentage by weight that will pass through a 150 micron sieve

Coarse limestone dust
Magnesian ground limestone Sedimentary rock consisting largely of calcium and magnesium carbonates and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 95% will pass through a sieve of 3.35 mm and not less than 40% will pass through a 150 micron sieve Neutralising value

Amount of material as a percentage by weight that will pass through a 150 micron sieve

Magnesian screened limestone Sedimentary rock consisting largely of calcium and magnesium carbonates and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 95% will pass through a sieve of 3.35 mm and not less than 20% will pass through a 150 micron sieve Neutralising value

Amount of material as a percentage by weight that will pass through a 150 micron sieve.

Course magnesian screened limestone Sedimentary rock consisting largely of calcium and magnesium carbonates and not more than 15% of magnesium expressed as MgO and of which 100% will pass through a sieve of 5 mm, not less than 90% will pass through a sieve of 3.35 mm and not less than 15% Neutralising value

Amount of material as a percentage by weight that will pass through a 150 micron sieve.

Course magnesian screened limestone dust
Chalk Cretaceous limestone Neutralising value
Ground chalk Cretaceous limestone of which 98% will pass through a sieve of 6.3 mm Neutralising value
Screened chalk Cretaceous limestone of which 98% will pass through a sieve of 45 mm Neutralising value
Ground burnt lime Commercial calcium oxide containing not more than 27% magnesium as MgO and of which 100% will pass through a sieve of 6.3 mm Neutralising value
Kibbled burnt lime Commercial calcium oxide containing not more than 27% magnesium as MgO and of which 100% will pass through a sieve of 45 mm Neutralising value
Burnt lime Commercial calcium oxide containing not more than 27% magnesium as MgO Neutralising value
Magnesian ground burnt lime Commercial oxide obtained from magnesian limestone containing more than 27% magnesium as MgO and of which 100% will pass through a sieve of 6.3mm Neutralising value
Magnesian kibbled burnt lime Commercial oxide obtained from magnesian limestone containing more than 27% magnesium as MgO and of which 100% will pass through a sieve of 45mm Neutralising value
Magnesian burnt lime Commercial oxide obtained from magnesian limestone containing more than 27% magnesium as MgO Neutralising value
Hydrated lime Product obtained obtained by slaking burnt lime or magnesian burnt lime of which not less than 95% will pass through a 150 micron sieve Neutralising value
Mixed lime A product resulting from mixing two or more forms of liming material specified in this schedule not being materials for which there is no minimum standard laid down in column 3 of this schedule, or material produced during the manufacture of commercial burnt lime or hydrated lime. Neutralising value

Amount of material as a percentage by weight that will pass through a 150 micron sieve

 

Note: The limits of variation (absolute value in percentage by weight) shall be 5% of the amount stated for all Declarations.

 
 
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