Build the canonical Acrisol fixture

Synthetic tropical-humid Acrisol on weathered gneiss: argic horizon at Bt1 with low-activity clay (CEC/clay ~ 17 cmol_c/kg clay) and low base saturation (BS ~ 25%). By construction:

• argic: PASSES on Bt1.

• acrisol: PASSES (CEC low, BS low).

• lixisol, alisol, luvisol: FAIL.

• Other diagnostics: FAIL.

Usage

make_acrisol_canonical()

Value

A PedonRecord.