# Lime rate calculator

This tool can be used to calculate lime rates to raise soil pH in acid sulfate soil areas.
Last updated: 2 May 2023

Where disturbance of acid sulfate soils is unavoidable, the most common way to manage the disturbance is to neutralise the soils with alkaline materials.

View the National acid sulfate soils guidelines for guidance. The guidelines also outline methods for soil neutralisation.

## Calculator

 Weight basis lime requirement - calculates the mass (in kg) of lime required to neutralise a mass (in tonnes) of ASS materials. Lime (kg /tonne soil) = (Net acidity(1) (%S x 30.59) x 1.02(2) x Safety Factor(3)) / ENV(4) Net acidity (% S) enter net acidity of ASS as %S(5) Safety factor enter adopted safety factor (DER default value is 1.5) ENV (%) enter ENV of neutralising material as a percentage Lime required (kg/tonne) :

 Volume basis lime requirement - calculates the mass (in kg) of lime required to neutralise a volume (in cubic metres) of ASS materials Lime (kg /m3 soil) = Soil bulk density x (Net acidity (%S x 30.59) x 1.02 x Safety Factor) / ENV Soil bulk density (tonne/m3) enter bulk density of ASS material in tonne/m3 Net acidity (% S) enter net acidity of ASS as %S Safety factor enter adopted safety factor (DER default value is 1.5) ENV (%) enter ENV of neutralising material as a percentage Lime required (kg/m3) :

Notes

1. Net acidity = potential acidity + existing acidity.
2. The factor 1.02 is used to stoichiometrically convert units of sulfuric acid (H2SO4) to units of calcium carbonate (CaCO3).
3. A minimum safety factor of 1.5 should be used.
4. The actual rate of application of neutralising materials required must be corrected for the effective neutralising value (ENV) (see National acid sulfate soils identification and laboratory methods manual.
5. For linear and non-linear disturbances involving soil volumes less than 1000m3, the highest net acidity detected at the site should be used to calculate the amount of neutralising material required. When the volume of soil to be disturbed is greater than 1000m3, the mean net acidity plus the standard deviation may be used to calculate the amount of neutralising material required, provided a statistically sufficient number of laboratory analyses have been performed to satisfactorily characterise the soil profile and acid sulfate soils at the site. Detrimental environmental impacts may occur if incorrect liming rates are used.

## Default bulk density values for soil types (to be used in the absence of site-specific data)

 Sand 1.6 Loamy sand 1.5 Sandy loam 1.4 Loam 1.3 Silty loam 1.2 Clay loam 1.1 Clay 1.05 Peat 1