The B textural as the book states it: a subsurface horizon of texture francoarenosa or finer, at least 7.5 cm thick (thickness items a to e), that meets one or more of the items below (v0.9.241).
(f) an E horizon above the B, the B having more clay than the horizons above it and being no B espodico, plintico or planico;
(g) a mudanca textural abrupta from the A or E to the B (Cap 1, p 30-31): at least twice the clay when the A or E has less than 200 g/kg, 200 g/kg more otherwise, within 7.5 cm. The distance is read from the distinctness of the transition (
boundary_distinctness: abrupt or clear); where it is not recorded the two layers are compared;(h) the relacao textural B/A of footnote 4, above 1.50, 1.70 or 1.80 according to the clay of the A (
test_ratio_textural_sibcs);(i) where the increase is below item (h), the cerosidade of one or more sub-horizons of the upper part of the B (read as its upper half): (1) texture media with no macroaggregates and cerosidade of moderate grade; (2) texture media with prismatic or blocky structure of moderate or strong grade and cerosidade of at least moderate grade; (3) texture argilosa or muito argilosa with that structure and cerosidade at least common and weak or few and moderate; (4) relacao textural of 1.4 or more with a fragipa within 200 cm, the B being no B espodico;
(j) with a discontinuity of parent material between the A or E and the B, or with only a ploughed layer above the B, items (h) or (i) are needed.
Amounts and grades written as ranges are read by their lower end, the requirements being minima. Lamellae (item d) are not tested.
Arguments
- pedon
A
PedonRecord.- ...
Passed to
argicfor a profile with no horizon designation; ignored otherwise.
Value
A DiagnosticResult recording whether the diagnostic is present, the qualifying layers, and the supporting evidence.
Details
Until v0.9.240 this function was the WRB argic horizon, whose
clay increase (6 percentage points, a ratio of 1.4 or 20 points, between a
layer and the least clayey layer anywhere above it) is not the one of the
book, joined to item (h); items (f), (g) and (i) were not tested.
The layers returned are the B sub-horizons (BC excluded) of texture
francoarenosa or finer; evidence$upper_layers are those that carry
the evidence, from the top of the B down.
The items are stated for the A, E and B horizons. A profile with no horizon designation at all (depth slices, for instance) cannot be read by them and is tested as before, by the clay increase between layers.
In the morphological mode
(options(soilKey.morphological_inference = TRUE)) a "t" in the
designation of a B horizon stands for the B textural when the items do not
show it. The diagnostic engine
(options(soilKey.diagnostic_engine = "aqp")) does not change this
test: it changed the argic horizon that this function used to be.