Lime Rate & Match It to Tillage Depth
Scales for shallow discing
A lime recommendation assumes a standard mixing depth — if you till shallower or deeper, scale the rate by your actual depth. Enter the recommended rate and depths to get the adjusted lime per hectare and the saving.
Match lime to your tillage
Next: apply 1,500 kg/ha for your 10 cm tillage — but if you only correct the shallow layer, re-test sooner since deeper acidity stays untreated.
Soil-test lime rates assume incorporation to a standard depth; shallow incorporation treats less soil mass. For no-till, surface-applied lime moves down very slowly.
Lime incorporation depth — key facts
- Adjusted rate
- recommended × (actual ÷ rec. depth)
- Saving
- recommended − adjusted
- Standard depth
- ≈ 15 cm (plough layer)
- Lime acts only
- where it is mixed in
- Shallower depth
- less soil → less lime
- Deeper depth
- more soil → more lime
- Disc mixes
- often only top 8–10 cm
- Privacy
- Runs in your browser; nothing uploaded
Lime only fixes the soil it actually touches
Lime barely moves in soil, so it neutralises only the layer it is physically blended with. A soil-test recommendation is written for a standard mixing depth — yet a disc may stir only the top eight centimetres while a deep plough inverts twenty or more. Apply the full rate into a shallow band and you over-lime that thin layer; apply it expecting deep mixing you never achieve and you under-treat the profile. Matching the rate to the real depth keeps the chemistry honest.
This tool scales the recommendation by your actual-to-recommended depth ratio and shows the adjusted lime per hectare and the saving. Use it to trim lime when you till shallow, to bump it up for a one-off deep correction, and to plan smaller, more frequent surface doses under reduced tillage. Pair it with the Lime from Base Saturation and Fertilizer Acidification Lime tools for the full liming picture.
Stop over-liming
Cut the rate when you only mix a shallow band.
Correct at depth
Bump lime up for a one-off deep incorporation.
See the saving
Know the lime and money matching depth saves.
Works either way
Scales up for deep till, down for shallow.
Frequently Asked Questions
How does this calculator adjust the lime rate?+
It scales your recommended lime rate by the ratio of your actual incorporation depth to the depth the recommendation assumed: adjusted rate = recommended rate × (actual depth ÷ recommended depth). Lime only neutralises the soil it is mixed into, so treating a shallower layer needs proportionally less lime, and a deeper layer needs more. The saving is the difference between the original and adjusted rates.
Why does incorporation depth change the lime needed?+
A lime recommendation is built for a standard tilled layer — often the top 15–20 cm. Lime is barely mobile, so it only reacts with the soil it is physically blended with. If you mix it into a shallower band you have less soil to neutralise and need less lime; if you plough it in deeper you have more soil and need more. Matching the rate to the real depth avoids over- or under-liming.
What is the standard recommended depth?+
Most soil-test lime recommendations assume incorporation through the plough or cultivation layer, typically 15 cm in many systems and up to 20–23 cm where deeper tillage is normal. Check what depth your lab or adviser used as the basis — that is the recommended depth to enter. The actual depth is how deep your own tillage will actually mix the lime.
I run reduced or no-till — does that mean less lime?+
In the very short term a shallow surface application treats only the top few centimetres, so the rate to neutralise that thin band is smaller. But surface-applied lime moves down slowly and acidity can build at depth, so most advisers split lime into smaller, more frequent surface doses rather than simply cutting the total. Use this tool to size the immediate shallow application, not to abandon liming the profile.
Can I use this to increase lime for deep ploughing?+
Yes. If you will mix lime deeper than the recommendation assumed — say a one-off deep cultivation to correct subsoil acidity — enter the deeper actual depth and the tool scales the rate up. You are then neutralising a larger soil mass, so the higher rate is correct. Deep incorporation is a good chance to apply a larger reserve dose.
Does it change the lime quality I need?+
No — this only adjusts how much lime to apply for your mixing depth. The output is still a recommendation-basis rate, so apply your usual material and account for its neutralising value separately. If the recommendation was already a product rate for a specific lime, the adjusted figure is the product rate for that same lime at your depth.
How do I measure my actual incorporation depth?+
It is the depth your tillage genuinely mixes the soil and lime, not the maximum the implement can reach. Dig a small pit after a pass and look for where the colour and structure change, or where surface residue is no longer mixed in. A disc may only blend the top 8–10 cm even if it runs deeper; a mouldboard plough inverts to near its full working depth.
Are the figures precise?+
They are solid planning figures based on a linear soil-mass relationship — half the depth, roughly half the lime. Real mixing is never perfectly uniform, so treat the result as a working rate and lean toward thorough incorporation. Re-test pH after a season, and if you lime shallow repeatedly, watch for acidity building just below your tillage layer.