Ultisols (USDA Cap 15): argillic/kandic horizon + base saturation < 35%.
Source:R/diagnostics-orders-usda.R
ultisol_usda.Rdv0.9.17 graceful BS handling: when bs_pct is missing in the
argillic layers, the diagnostic falls back to two equivalent
indirect criteria before failing:
al_sat_pct >= 50(high Al saturation mathematically forces BS < 50, and BS < 35 in essentially all tropical soils with this profile);ph_h2o < 5.0(the empirical threshold below which BS exceeds 35 in fewer than 5
The fallback only fires when the direct measurement is missing, so lab-grade profiles always use the canonical KST 13ed gate.
Arguments
- pedon
A
PedonRecord.