ANDOSOLS OF EUROPE
Soil Resources of European Volcanic Systems

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AZORES SOIL PROFILES

PROFILE EUR06 - PAZ
Pico island, Azores - may 1999

Date of description: 01-05-1999

Authors: A.G. Jongmans, and F. van Oort

Location: Portugal, Azores, Pico Island

Altitude: 400 m

Co-ordinates:

Map number and Co-ordinates:

Classification:
WRB (2001): Hydri-silandic Andosol (Umbric and Acroxic)
ST (1999): Hydrous, amorphic, mesic Acrudoxic Hydrudand

Click on image to enlarge

Soil Climate: Mesic temperature regime, Udic moisture regime.

Topography: Hilly

Landform: Volcano

Land element: Slope,

Position: Middle slope

Slope: Located on a sloping (5-10%) slope; main slope is moderately steep

Form: Straight slope.

Landuse/Vegetation: Forest, Cryptomeria japonica, Pittosporum undulatum, Erica agorica, Rubus, Fern

Human influences: Profile is situated in a road cut, renewed for 1 m.

Parent material: Basaltic pyroclastic material.

Effective soil depth: Deep

Erosion: No erosion features visible.

Drainage class: Moderately well drained.

Moisture conditions: Moist

SOIL HORIZON DESCRIPTION:

Ah: 0-35/40 cm; dark reddish brown (5YR 3/2); clay loam; strong very fine granular in clustered distribution pattern, and strong fine and medium subangular blocky structure; very friable; common very fine and fine pores; few to common fine to medium roots; charcoal fragments; clear and smooth to:

AB: 35/40-40/50 cm; dark brown (7.5YR 3/4); clay loam; few fine subrounded totally altered gravel; pockets of strong very fine granular structure; strong fine and medium angular and subangular blocky structure; very friable; few to common very fine and fine pores; few fine and medium roots; dead roots, partially decomposed are present; clear and smooth to:

2AB: 40/50-60/70 cm; dark brown (7.5YR 3/2); clay loam; few partially and totally weathered subrounded gravel, dark reddish brown (2.5YR 3/4), thixotropic; dominantly moderate fine (sub)angular blocky structure, in channels strong very fine granular structure; common very fine and fine pores; few fine roots, partially decomposed; gradual and smooth to:

2Bw1: 60/70-95/100 cm; dark brown (10YR 3/3); clay loam; few totally weathered gravel, dark reddish brown (2.5YR 3/4); very weak coarse prismatic structure, subdivided into strong very fine angular blocky structure; in channels locally strong fine granular structure; friable; common very fine and fine pores; few fine and medium roots; few dead roots; gradual and smooth to:

2Bw2: 95/100-125 cm; dark brown (7.5YR 3/4); clay loam; common fine medium and coarse totally and partially weathered gravel, in vesicles in the fragments yellowish/white allophane coatings; moderately fine angular blocky structure; friable; many fine and very fine pores; very few fine roots; dead roots present; clear and smooth to:

2Bw3: 125-140 cm; reddish brown (5YR 4/4); clay loam; many fine to medium and coarse subrounded fresh, partially and totally weathered gravel; common very fine and fine pores; few fine roots; dead roots present; abrupt and smooth to:

3C: >140 cm; dusky red (2.5YR 3/2); alteration of bands of fine gravel and gravely clay loam; bands are thixotropic; yellowish fine textured coatings.

 

 

WRB (2001): umbric horizon (0-35/40 cm; no fulvic or melanic horizon because of too high colour value); andic horizon (0-140 cm); Sio > 0.6% between 0 and 100 cm; moisture content more than 200% between 35 and 100 cm; ECEC < 2 cmol(+) kg-1 fine earth between 70 and 100 cm:

Hydri-Silandic Andosol (Umbric and Acroxic)

 

ST (1999): umbric epipedon (0-35/40 cm; no melanic epipedon because of too high colour value): andic soil properties (0-140 cm); moisture content more than 200% between 35 and 100 cm; ECEC < 2 cmol(+) kg-1 fine earth between 70 and 100 cm; 8x Sio + 2x Feo > 5; 8x Sio > 2x Feo, except in the first two horizons (covering 0-30 cm) according to Wageningen/Nancy figures:

Hydrous, amorphic, mesic Acrudoxic Hydrudand

(Note: the combination of Hydrous and Hydrudand does not seem to be excluded in Soil Taxonomy)


Last modified 30 April 2004 by EG