Liming Materials & Cheapest Per Effective Tonne

Because liming materials differ in how much acidity they neutralise and how fast they react. A cheap product with low calcium carbonate equivalent or coarse particles does less work per tonne, so you must spread more of it to get the same result. The honest comparison is cost per effective tonne — the price for a tonne of actual neutralising power, not a tonne of material.

CCE, or neutralising value, is a material's acid-neutralising power expressed as a percentage of pure calcium carbonate. Pure calcite is 100%; dolomite is around 108%; quicklime and hydrated lime are higher. A product at 90% CCE neutralises 90% as much acidity per tonne as pure limestone, all else being equal.

Fineness measures how finely the lime is ground. Fine particles have more surface area, dissolve faster and react with the soil sooner; coarse particles can sit for years doing little. Fineness is captured as a percentage efficiency factor, so a coarse product effectively delivers less of its CCE within a useful timeframe.

ENV combines quality and reactivity: ENV = CCE × fineness. It is the share of a material that actually neutralises acidity in a reasonable time. A lime at 95% CCE that is only 70% fine has an ENV of about 67%, so two-thirds of each tonne does the job. ENV is the number to compare products on.

Material needed (t/ha) = pure-lime requirement ÷ (ENV ÷ 100). If your soil test calls for 3 t/ha of pure lime and your product has an ENV of 75%, you need 3 ÷ 0.75 = 4 t/ha of that product. The tool does this for both materials so you can see the real application rates side by side.

Cost per effective tonne = price ÷ (ENV ÷ 100). It tells you what a tonne of genuine neutralising power costs after adjusting for quality. The tool also shows cost per hectare (material needed × price), then names the cheaper material and the saving versus the other one.

Choose dolomitic lime (calcium-magnesium carbonate) when your soil is also short of magnesium, since it supplies both nutrients while raising pH. On soils with adequate magnesium, calcitic lime is usually fine and may be cheaper per effective tonne. The comparison still comes down to ENV and price for the neutralising job.

Quicklime (calcium oxide) and hydrated lime (calcium hydroxide) have very high CCE and react quickly, so they raise pH fast and you need less by weight. But they are caustic to handle, can scorch if over-applied, and usually cost more per tonne. They suit situations needing a rapid pH lift rather than routine maintenance liming.

Get it from a buffer-pH (lime requirement) soil test, which measures the soil's reserve acidity and reports how much pure lime per hectare is needed to reach your target pH. Enter that pure-lime figure here, and the tool converts it into the actual tonnes of each product you must spread.

It is a sound planning comparison. Real results depend on accurate CCE and fineness data from the supplier, even spreading, soil mixing and time for reaction. Use the supplier's declared neutralising value and fineness where possible, and treat the cost per effective tonne as the fair basis for choosing between products.