Tests whether the profile shows fluvic material features: alternating textures across consecutive horizons within the upper 100 cm AND an irregular (non-monotone) organic carbon pattern with depth. Diagnostic of Fluvisols.
Arguments
- pedon
A
PedonRecord.- max_top_cm
Maximum top depth (cm) considered (default 100).
- min_clay_swing
Minimum absolute clay-percent change between consecutive layers required to count as alternation (default 8 percentage points).
Details
Sub-test: test_fluvic_stratification.
v0.3 limitations: WRB 2022 fluvic material also requires age (typically <100 years for sediment freshness), which v0.3 does not check (no temporal fields in the schema). The stratification proxy is conservative – truly heterogeneous floodplain profiles with dramatic texture swings will pass; subtle alluvial sequences may miss. v0.4 will refine.
v0.9.314
Fluvic material follows WRB 2022 Ch 3.3.6 (p. 87) layer by layer:
fluviatile, marine or lacustrine origin (rock_origin,
layer_origin, else the site's parent material); strata that are
obvious (the clay reversal above, or a sand reversal of \(\ge\) 15%) OR
evidenced by two or more layers with more SOC than the layer directly above
(\(\ge\) 0.2%, \(\ge\) 25% relative and \(\ge\) 0.2% absolute,
not of a natric or spodic horizon); and a single grain, massive, platy or
weak subangular blocky structure (granular or subangular blocky in a layer
of higher SOC). The layers returned are those that meet the three. An
origin, a texture or a structure that is not recorded leaves the result
undecided. The SiBCS carater fluvico keeps the earlier reading.