Resources / Grain / Soil pH
Grain · Soil & nutrition · Soil

Soil pH

5.6 pHCa

Topsoil acidity measured in calcium chloride, tracked over time against the target. pH is the master variable of the root zone: it governs nutrient availability, aluminium and manganese toxicity, nodulation in legumes and the persistence of the whole rotation.

Worked example · Topsoil pH(CaCl₂) · after liming · 4 yrs
Target pHCa 5.5 5.1 5.2 5.4 5.6 2023 2024 2025 2026
Topsoil pH(CaCl₂) · after liming · 4 yrs
The benchmark

For most crops the target topsoil pH is above 5.5 in calcium chloride; below about 5.2, aluminium becomes available and starts to prune roots and cap yield, especially in acid-sensitive crops.

NSW DPI Acid Soils ↗
What it signals

Acidity develops slowly and invisibly, then constrains everything — a rising trend after liming shows the investment is working, while a stalled or falling one warns that acidification is outrunning your lime program before yields ever flag it.

Data required to calculate
Topsoil pH(CaCl₂)pHSubsurface pHpHLime appliedt/ha

Silo pulls each of these from the sources the operation already uses, and keeps the figure current automatically.

How to improve it
01

Apply lime to budget, matched to buffering capacity and target pH.

02

Monitor subsurface acidity, not just the top 10 cm, before it hardens.

03

Use acid-tolerant varieties and species as a bridge while pH recovers.

Questions & answers

What is soil ph?

Topsoil acidity measured in calcium chloride, tracked over time against the target. pH is the master variable of the root zone: it governs nutrient availability, aluminium and manganese toxicity, nodulation in legumes and the persistence of the whole rotation.

What data do you need to calculate soil ph?

You need: Topsoil pH(CaCl₂) (pH), Subsurface pH (pH), Lime applied (t/ha). Silo pulls each of these from the sources the operation already uses and keeps the figure current automatically.

What is a good soil ph benchmark?

For most crops the target topsoil pH is above 5.5 in calcium chloride; below about 5.2, aluminium becomes available and starts to prune roots and cap yield, especially in acid-sensitive crops.

How do you improve soil ph?

Apply lime to budget, matched to buffering capacity and target pH. Monitor subsurface acidity, not just the top 10 cm, before it hardens. Use acid-tolerant varieties and species as a bridge while pH recovers.

More grain guides

All grain KPIs →

See this KPI live for your own operation.

Connect the software, spreadsheets and records you already keep, and Silo keeps every benchmark on this page current automatically.

Book a demo