ICELANDIC SOIL PROFILES

PROFILE EUR08 - IS
Audkuluheidi - August 1999

Date of description: 27-08-1999 Authors: A.G. Jongmans, F. van Oort and O. Arnalds Location: Central North Iceland, Audkuluheidi Altitude: About 400 m GPS co-ordinates: x 5551000, y 7251900 Map number and co-ordinates: Classification:    WRB (2001): Dystri-Vitric Andosol ST (1999): Ashy, amorphic Typic Vitricryand

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Soil Climate: Cryic temperature regime, Udic moisture regime. Mean annual rainfall 800 mm; mean annual temperature 1.0°C, mild winter, frost 6-9 months in soil; snow cover 3-7 months

Topography: Gently rolling

Landform: Upland glacial plain

Land element: Slope

Position: Bottom

Slope: Nearly level

Micro topography: Hummocky area, hummocks 10-30 cm high and 0.5-2 m2 in size, but considerable variation in shapes and sizes.

Landuse/Vegetation: Communal grazing land for sheep; 80% vegetation cover. Heath with about 50% Rachomitrium moss, with Betula nana, Empetrum, Vaccinium heath and kobresia sp.; vegetation strongly influenced by land use.

Human influences: 

Parent material: Glacial moraine under 50-100 cm thick aeolian and volcanic ash

Effective soil depth: Moderately deep

Erosion: Water and wind erosion, dominantly active in historical times.

Drainage class: Well drained.

Internal drainage: Frost cracks on surface, rarely saturated; moderately hydraulic conductivity

External drainage: Slow run-off

Moisture conditions: Moist

SOIL HORIZON DESCRIPTION:

O:             0-3 cm; partially decomposed organic materials; abrupt and smooth to:

Ah1:          3-11/19 cm; dark brown (7.5YR 3/3); sandy loam; moderate fine to medium platy; friable; many fine to medium roots; from 12-16 cm irregular bright dark yellowish brown (10YR 4/5) spots, 1 cm; abrupt and wavy to:

Ah2:          11/19-21/27 cm dark reddish brown (5YR 3/3); sandy loam; no macro structure; very friable; no biopores detectable; common fine roots; abrupt and tonguing to:

Bw1:         21/27-26/34 cm; brown to dark brown (7.5YR 4/4); sandy loam; no macro structure; very friable; few fine pores; common fine roots; abrupt and tonguing to:

2Bw2:       26/34-37/42 cm: yellowish brown (10YR 5/5); bright discontinuous tephra layer, slightly weathered; sandy loam; moderate fine platy structure; friable; common fine roots; occurrence of cryoturbation features, presence of material from the over- and under-laying horizons; abrupt and wavy to:

3Bw3/4C:  37/42-59/62 cm; 70 % Bw 7.5YR 3/5; 30% 4C, glacial till material, dark yellowish brown (10YR 4/4); loam; few fine gravel, sub rounded, up to 3 cm, slightly weathered; no macro structure; friable; few, fine roots; abrupt and smooth to:

4C:            >59/62 cm; glacial till; dark yellowish brown (10YR 4/4); sandy clay loam; fine gravel to boulders, sub rounded, partly weathered; layers of 2 cm consisting of 3Bw material, distributed inclined to the soil surface as a result of cryoturbation; no macro structure; friable; few fine roots in the upper 10 cm.

WRB (2001): ochric horizon (O + Ah1 + Ah2 too thin to constitute together a mollic horizon); no andic horizon (too high glass content between 21/27 and 59/62 cm) starting within 25 cm; below 59/62 cm too low P-retention for andic horizon; vitric horizon at least between 21/27 and 59/62 cm (10% or more volcanic glass, Al_o + ½ Fe_o > 0.4%, P-retention > 25%); no cryic horizon assumed between 26/34-37/42 cm despite cryoturbation features ((soil) temperature >0^oC); BS < 50% in some part between 20 and 100 cm (47% between 37/42 and 59/62 cm):

Dystri-Vitric Andosol

ST (1999): ochric epipedon (O + Ah1 + Ah2 too thin to constitute together a mollic horizon); andic soil properties (0->59/62 cm); no permafrost or gelic materials within 100 cm; 8x Si_o + 2x Fe_o > 5, 8x Si_o > 2x Fe_o:

Ashy, amorphic Typic Vitricryand