The Albrecht Method — Base Cation Saturation Ratios

Soil management approach based on the work of William Albrecht (University of Missouri, mid-20th century), focusing on the balance of base cations — particularly calcium (Ca) and magnesium (Mg) — rather than pH alone. Presented by Steve Townsend in Direct Driller Issue 3.

Core Principle

Calcium and magnesium should together account for approximately 80% of base saturation in the soil:

Cation Ideal range (% base saturation)
Calcium (Ca) 60–70%
Magnesium (Mg) 10–20%
Ca + Mg combined ~80%

pH alone is insufficient as a guide to soil health. Two soils at the same pH can have very different Ca:Mg ratios and behave very differently.

[Source: dd-issue-03, 2026-04-11]

Effects of Incorrect Ca:Mg Balance

Excess Magnesium

  • Causes clay dispersal — soil particles separate rather than aggregating
  • Results in compaction and poor soil structure
  • Waterlogging risk increases
  • Creates conditions favourable to blackgrass germination and persistence

Correct Ca:Mg Balance

  • Ca acts as a soil flocculant — promotes aggregate formation
  • Improved soil structure and drainage
  • Steve Townsend’s key claim: blackgrass hates correct Ca:Mg levels — correcting the balance can reduce blackgrass pressure independently of herbicide programmes

[Source: dd-issue-03, 2026-04-11]

Practical Application

  • Test soil for full base saturation percentages, not just extractable nutrients
  • Where Mg is high relative to Ca, apply gypsum (calcium sulphate) or lime to shift the ratio
  • Regular monitoring — the ratio matters more than individual absolute levels
  • Simon Cowell (Soil Farmer of the Year 2018) applies gypsum in his compost to counteract high Mg on his heavy clay (see Soil Farmers of the Year 2018)

[Source: dd-issue-03, 2026-04-11]

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