From the Soil Micromorphology Slide Collection

Micromorphological description of slide: The tapetum embedded in the mineral matrix remains as a remnant of a magasporangium.

Data for the horizon
Horizon sampled: Ap
Depth sampled: 0-1 5 cm
Physical and chemical data available: pH = 5.9, org. c = 1.45%, N = 0.14%, exch.Ca = 71 .9%, exch. Mg = 22.2%, exch. K = 2.00%, exch. Na = 0.23%, total exch. cap. (cmol (p +)/kg) = 13.0, clay — 16%, clay mineralogy = hydrous mica > kaolinite > smectite.
Micromorphological description of horizon: The upper 10 cm of the Ap horizon has separated zones of vughy porphyric (60%) and matrigranoidic (40%) fabrics made up of moderately differentiated and a few discrete and irregular meso and macro granic units. The 10-14 cm depth has a porphyric fabric arrangement. In the upper section voids (50%) are dominantly orthovughs (7/10) of varying size; some macro and mega channels (2/10) and compound packing voids (1 / 10) are also present. In the lower section voids (30%) are made up of meso skew planes (5/10), meso and macro channels (3/10), and meso vughs (2/10). Fecal pellets make up 2-5% of the fabric. Strongly welded earthworm fecal pellets occur largely in aggrotubules. Fecal pellets of Diptera (fly) larvae and Collembola (springtails) are found in old root channels. Sporangia and fungal hyphae are common along the root surface.
Macromorphological description of horizon: Ap (0-15 cm): Dark grayish brown (IOYR 4/2, m) sandy loam to loam; crumby to massive and fragmented; friable to firm; abrupt smooth boundary.

Data for thin section
Preparation of sample: Air dry
Impregnating medium: Epoxy
Thickness of section: 30 µm
Orientation of section: Vertical

Soil Classification
U.S.: Typic Cryoboralf F.A.O.: Albic Luvisol
Canada: Orthic Gray Luvisol

Elevation: 700 m above sea level
Topography and hill slope position: Level to undulating upper slope Parent material: Till
Soil climatic data and/or soil water balance: Subhumid moisture regime and cold soil temperature class
Vegetation: Cultivated field of faba beans (Vicia faba)

Data for 35-mm slide
Frame length: 0.2 mm
Light mode: Plane polarized

Pawluk, S. 1980. Micromorphological investigations of cultivated Gray Luvisols under different management practices. Can. J. Soil Sci. 60: 731-745.
Source - S. Pawluk

Slide BF41. Soil Science Society of America, 1993. A Reference Slide Collection for Soil Micromorphology. SSSA, Madison, WI.