
Test for fluvic stratification: irregular OC pattern + texture variability across consecutive horizons
Source:R/utils-diagnostic-tests.R
test_fluvic_stratification.Rdv0.3 simplified: returns TRUE when (a) at least 3 layers within the upper 100 cm exist, AND (b) clay_pct varies by >= 8 percentage points across consecutive layers (indicating depositional alternation), AND (c) OC does not decrease monotonically with depth.