Soil Chemistry Calculators
Lime, pH, CEC, base saturation, gypsum and irrigation water quality — the measurements that decide whether an amendment plan works.
Lime Rate
Turn buffering capacity (CEC, buffer pH or OM%) into tons of ag lime per acre, adjusted for ECCE and ENV.
Open calculatorpH Down
Elemental sulfur, iron or aluminum rates to hit a target pH — with acidifier comparison and rebound warnings.
Open calculatorCEC
Convert lab ppm to meq/100g and read total CEC, base saturation and cation balance from one soil test.
Open calculatorBase Saturation
Balance Ca, Mg, K and Na against Albrecht targets with a saturation donut, what-if simulator and plan.
Open calculatorGypsum
Sodic soil reclamation: exchangeable sodium percentage into tons of gypsum per acre by source purity.
Open calculatorSAR / CROSS
Irrigation water quality — sodium adsorption ratio, CROSS and adjusted SAR with dispersion diagnostics.
Open calculatorWhy soil chemistry comes first
Fertilizer decisions are only as good as the chemistry underneath them. Before you buy product, you need to know how much lime it takes to move pH, how much charge your soil actually holds, and whether calcium, magnesium and potassium are competing for the same exchange sites.
Each calculator below starts from a standard lab report — cations in ppm or meq/100g, buffer pH, organic matter percentage, or irrigation water analysis — and prints the derivation alongside the result so you can check it against your own spreadsheet.
Reading the numbers
CEC (cation exchange capacity) is the size of the nutrient reservoir, expressed in meq/100g. Base saturation is how that reservoir is divided between calcium, magnesium, potassium, hydrogen and sodium. The Albrecht school targets roughly 65–75% Ca, 10–20% Mg and 3–5% K; other programs run wider ranges, which is why every tool here shows its target rather than assuming one.
Lime requirement depends on buffering, not just active acidity. A soil at pH 5.8 with a high CEC can need far more lime than a sandy soil at pH 5.0, because there are more exchange sites to neutralise.
Pair them with fertigation tools
Once the soil chemistry is set, the 2 fertigation calculators handle blend formulation and PPM-to-EC conversions: Blend, PPM → EC.
Across the full suite there are 8 calculators — all free, all running in your browser.