From the Soil Micromorphology Slide Collection

Description of slide: Rather densely packed aggregates consisting of strongly welded crumbs between which mammilated vughs with curved planes are common. There are few fine iron oxide nodules and concretions.

Data for the horizon Horizon sampled: Bs1 Depth sampled: 40-55 cm
Physical and chemical data available: pH = 6.1, OC. = 0.2%, free Fe203 = 8.9% Particle size distribution (deferrated): sand = 2%, silt = 11%, clay = 87%
Clay mineralogy: Gibbsite dominant, goethite present
Macromorphological description of horizon: 5YR 4/6 clay with many 5YR 5/6 coatings along fine tubular pores; weak coarse and medium subangular blocky parting to fine and very granular structure
Micromorphological description of horizon: Dominantly inorganic plasma, reddish brown to yellowish red, due to iron and few organic pigments. The plasmic fabric is inundulic to insepic. Skeleton grains are rare, mostly fine sand- and silt-size. Few root remains still occur. Related distribution pattern is porphyroskelic (Stoops and Jongerius, 1975: c/f 2 µm open porphyric ) .


Soil Classification
U.S.: Clayey, gibbsitic, isohyperthermic Typic Acrudox
F.A.0.: Acri-Orthic Ferralsol

Elevation: 390 m above mean sea level
Physiographic position: Karst depression floored with bauxite deposits surrounded by limestone hills
Topography and hill slope position:Nearly level to gently undulating
Parent material:Bauxite overlying limestone of the White Limestone Formation
Soil climatic data and/or soil water balance: Annual rainfall approximately 2000 mm
Vegetation:Citrus orchard with grass undergrowth in a tropical rainforest climate

Data for 35-mm slide
Light mode: Plane polarized
Scale: Bar on slide = 250 µm

Andriesse W. and J. J. Scholten. 1982. Acri-Orthic Ferralsol (Haplic Acrorthox) Jamaica. ISM Soil Monolith Paper 6. International Soil Museum, Wageningen, The Netherlands.

Slide MS3. Soil Science Society of America, 1993. A Reference Slide Collection for Soil Micromorphology. SSSA, Madison, WI.