3D Soil Exchange Complex & pH Buffering Simulator

Soil profile composition

Clay content 30%

Organic matter 4%

Amend the soil

Dose per click 2.0 meq/100g

CEC

–

Base saturation

–

Soil pH

–

Buffer capacity β

–

How it works

Each clay platelet in this soil column carries exchange sites populated by orbiting cation spheres: blue for base cations (Ca²⁺, Mg²⁺, K⁺), red for acid cations (H⁺, Al³⁺). CEC here is built from two real contributions — mineral clay surface area and organic matter — rather than a texture preset, so you can see continuously how each one buffers the exchange complex.

CEC ≈ 0.5·clay% + 3.0·organicMatter%   (meq/100g, rule-of-thumb)
f = baseMeq / CEC
pH = pKa + log10( f / (1−f) )
β  = 2.303 · CEC · f · (1−f)

Clay content — more mineral colloid surface area means more permanent exchange sites.
Organic matter — humus contributes disproportionately more CEC per percent than clay does, which is why organic-rich topsoil buffers pH so well.
Add acid / Add lime — same cation-exchange chemistry as a real amendment: sites swap occupants, not total count.

Real-world relevance: this is the same reasoning behind soil test recommendations — a sandy, low-organic-matter field needs far less lime to move its pH than a heavy clay or peat soil, because its buffer capacity β is much smaller.

Base cation (Ca²⁺/Mg²⁺/K⁺) Acid cation (H⁺/Al³⁺) Clay/humus colloid

⚠ Couldn't load the 3D engineThree.js failed to load from the CDN. Check your connection and reload.