Technical Information

LIME LOSSES

Unless steps are taken to redress the balance of soils by applying a liming material there will be a natural reduction in the lime status of most soils. This results in a natural increase in acidity and in many cases a reduction in soil fertility and damage to soil structure.

Losses occur as a result of:

LOSS MECHANISMS

A lime loss diagram will help to explain the following points on lime loss. Plants make the soil more acid by:

• Organic and inorganic acids formed during decomposition of crop residues (acid forming)
• Plants remove calcium and magnesium from the soil (acid forming)
• Deep tillage may bring acid subsoil into the root zone (acid forming)
• Plants release hydrogen ions (H+) to the soil (acid forming)

Acid precipitation

The products of fossil fuel combustion from power plants, industry and motor vehicles are returned to earth in rainfall as nitric and sulphuric acid.

Leaching

Calcium and magnesium can be carried out of the root zone by the downward movement of soil water, frequently in association with nitrate (NO3-)

Ammonium rich fertilisers

Ammonium nitrate rich fertilisers contribute to soil acidity by nitrification of ammoniacal (NH4) nitrogen to nitrate which releases hydrogen ions.

NEXT > Lime Loss Mechanisms

The advisory booklet 'Agricultural Lime, the natural solution' is available from the ALA. Click HERE to order a copy by email.