Free · Instant · In-browser

Base Saturation & Lime It Up to Target

Neutralises exchangeable acidity

Lime kg/haLime t/haAcidityWhole field

“Your 5-star review is a signal. Your 2-star review is a gift.

From your soil CEC, current and target base saturation, bulk density and depth, get the exchangeable acidity to neutralise and the lime (CaCO₃ equivalent) in kg/ha, t/ha and for your whole field.

Set your soil & target

CEC

cmol/kg

Cation exchange capacity from soil test

Current base sat.

Target base sat.

Bulk density

g/cm³

Incorporation depth

Field area

Unit

Your result

2.3 t/ha

Agricultural lime to apply

2,340 kg

Lime per hectare

2.4

Acidity cmol/kg

1 ha

Field area

2.3 t

Lime per hectare

What this means

To lift base saturation you must neutralise the exchangeable acidity sitting on the CEC. Here raising from 55% to 75% across a 12 cmol/kg CEC means displacing 2.4 cmol/kg of acidity over a 15 cm layer, which works out to 2.3 t/ha of lime.

Next: spread 2.3 t/ha (2,340 kg/ha) of quality ag-lime and incorporate to 15 cm; re-test base saturation after 6–12 months.

Assumes pure CaCO₃ equivalent; divide by the lime's neutralising value (ENV/CCE) if using a lower-grade material. Base saturation targets vary by crop and clay type.

Lime from base saturation — key facts

Acidity: CEC × (target − current) ÷ 100
Lime: acidity × 0.0005 × soil mass
Good base sat.: ≈ 70–80% for most crops
Soil mass: depth × bulk density × area
Held by bases: Ca, Mg, K cations
Held by acids: H⁺ and Al³⁺
Result is: pure CaCO₃ equivalent
Privacy: Runs in your browser; nothing uploaded

Lime by the cation chemistry, not just the pH

When you have a full soil-test cation panel, the most direct way to size lime is to ask how much acidity sits on the exchange sites and how much of it you want to swap for calcium. That is the gap between your current and target base saturation, scaled by the soil's CEC. Multiply by the soil mass in the layer you are treating and you have the lime to spread — a method favoured where reserve acidity, not just the surface pH, drives the decision.

This tool computes the exchangeable acidity and the lime in kg/ha, t/ha and total from CEC, base saturation, bulk density, depth and area. Use it to plan a precise liming dose, then divide by your lime's neutralising value to get the real product weight. Pair it with the Fertilizer Acidification Lime and Lime Incorporation Depth tools to build and then hold the right base saturation.

Cation-accurate

Sizes lime from CEC and base saturation, not a guess.

Whole-field tonnes

Scales the rate to your area in any unit.

Shows the acidity

See the exchangeable acidity the lime must overcome.

Plan to a target

Hit the exact base saturation your soil test sets.

Frequently Asked Questions

How does this calculator find the lime needed?+

It first works out the exchangeable acidity you must neutralise: CEC × (target − current base saturation) ÷ 100, in cmol(+)/kg. It then converts that to lime using the soil mass in the tilled layer — depth, bulk density and area — at 0.0005 tonnes of CaCO₃ per cmol per kilogram of soil. The output is the lime in kg/ha, t/ha and for your whole field.

What is base saturation?+

Base saturation is the share of a soil's cation exchange capacity that is held by the base cations calcium, magnesium and potassium, rather than by acidic hydrogen and aluminium. A higher base saturation means a less acidic, better-buffered soil. Liming replaces the acidic cations with calcium, raising the base saturation and the pH together.

What target base saturation should I aim for?+

Most productive arable and pasture soils sit well at 70–80% base saturation, which corresponds to a comfortable, near-neutral pH for the majority of crops. Some growers following the BCSR (cation balance) school aim higher; many agronomists are happy anywhere the pH and calcium supply are adequate. Enter the target your soil test or adviser recommends and the tool gives the lime to reach it.

Why do CEC, bulk density and depth all matter?+

The acidity is per kilogram of soil, so the actual lime depends on how much soil you are treating. A higher CEC holds more acidity per kilo; a deeper incorporation or a denser (higher bulk density) soil means more total soil mass to neutralise. Together they convert the per-kilogram acidity into a real field rate, which is why all three are inputs.

How is this different from a pH-based lime calculator?+

A pH or buffer-pH method estimates lime from how the pH responds to acid; this method works directly from the cation chemistry — how much acidity sits on the exchange sites and how much you want to swap for bases. It is the approach used when you have a full soil-test cation panel (CEC and base saturation). Both should land in a similar range on the same soil.

What is exchangeable acidity?+

Exchangeable acidity is the hydrogen and aluminium held on the soil's exchange sites, expressed in cmol(+)/kg. It is the reserve acidity that lime must neutralise to move the pH and raise base saturation — far larger than the active acidity you read as pH. This tool computes the acidity gap between your current and target base saturation, which is exactly what the lime has to overcome.

Do I need to adjust for lime quality?+

Yes. The result is a pure calcium-carbonate equivalent. Field lime is rarely 100% pure or perfectly fine, so divide the figure by your material's neutralising value (often 0.80–0.95) and account for fineness to get the actual product to spread. The Liming Material Comparison tool helps you pick the cheapest effective source.

Are the figures precise?+

They are solid agronomic planning figures from your soil-test inputs. Real lime response varies with mineralogy, the lime's fineness and how evenly it is mixed, so re-test base saturation and pH after a season to confirm. Treat the result as a working dose, apply it well-incorporated, and fine-tune the next round from the new soil test.

Related farming tools

Fertilizer Acidification Lime Calculator Lime Incorporation Depth Calculator Manure Mineralization Calculator Variable Rate Fertilizer Zone Calculator Soil & Fertilizer Farming Hub

Explore the toolkit

1900+ free tools, zero sign-up

Calculators, developer & SEO utilities, data, content, hardware and farming — all instant, private and in your browser.

Browse all tools

Calculator

Base Saturation & Lime It Up to Target

Set your soil & target

Lime from base saturation — key facts

Lime by the cation chemistry, not just the pH

Cation-accurate

Whole-field tonnes

Shows the acidity

Plan to a target

Frequently Asked Questions

Related farming tools

1900+ free tools, zero sign-up

Power

Biofertilizer Dose Calculator

CSV Pro

Burn Rate & Runway Calculator

llms.txt Generator

Hardware Benchmark Database Pro

Password Strength Tester

Which LLM Can My PC Run?

Pressure

Biosolids & Manure Heavy-Metal Loading Calculator

cURL to Documentation Converter

Customer Lifetime Value (CLV) Predictor

Meta Tags Studio

Hardware Specifications Explorer

Password Tools

LLM VRAM & Speed Estimator

Radians ↔ Degrees Unit Circle

Bone Meal Phosphorus Calculator

GraphQL Query Example Generator

Market Sizing Calculator

Readability Checker

CPU & GPU Tier List Pro

Local LLM Hardware & Model Directory

Salt