Reference soil Ecuador 13: Regosol

EC013

Regosols are found in areas where soil has been eroded to the extent that the underlying unconsolidated materials come near to the surface, or where soil formation has not played an important role, e.g. in desert regions. The name comes from the greek 'rhegos' :blanket meaning young soils on weathering materials.

Characteristics

Soils in medium and fine textured materials, having no distinctive horizons other than an ochric horizon at the surface.

Distribution of Regosols (rough estimation supplied by soilgrids)

Reference soil EC013: Regosols

EC13 is comparable to profile Ecuador no.7 in: part III-tourguide for Ecuador of the sixth international soil classification workshop (1984). The soil has been redescribed and resampled by G.del Posso in May 1988, additionally two monoliths has been taken. The soil from 0 to 35cm is disturbed by digging, therefore no thin surface horizon has been separated. From 0 to 70 cm are present a few artifacts like charcoal, bricks etc. The grass layer consists of herbs and Kikuyu grass. Adjacent to the Eucalyptus plant are is a maize field.

Classification

WRB 2006

WRB 1998

Haplic- Regosol (Tephric Hypereutric Arenic)

Tephri-Arenic- Regosol (Hypereutric)

tephric

0-69 cm	ochric horizon
-	tephric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Eutric Regosol

Vitric Andosol

0-69 cm

ochric A horizon

0-69 cm

ochric A horizon

Local classification:	Suelo Arenoso

Other classification

USDA-SCS (1975)

Ustipsamment ustic ashy over loamy mixed isothermic

Physical characteristics

Particle size distribution

Depth (cm)	Gravel % v/v	very coarse sand % w/w	coarse sand % w/w	medium sand % w/w	fine sand % w/w	very fine sand % w/w	Total sand % w/w	coarse silt % w/w	fine silt % w/w	Total silt % w/w	Clay % w/w
0-33	0	3.8	15.5	25.3	19.3	10.8	74.7	11.0	10.8	21.8	3.4
33-69	0	5.5	14.0	21.7	20.8	9.1	71.1	10.6	14.6	25.2	3.6
69-87	0	5.4	14.3	21.8	20.6	7.9	70.0	8.8	18.0	26.8	3.2
87-110	0	9.4	15.5	18.5	18.4	7.9	69.7	9.4	15.9	25.3	4.9
110-150	0	0.7	3.0	10.8	22.4	14.1	51.0	15.8	21.2	37.0	21.2

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-33	-	-	-	0.0	3.4
10-35	1.290	-	-	-	-
33-69	-	-	-	0.0	3.6
110-140	1.350	-	-	-	-
69-87	-	-	-	2.7	3.2
87-110	-	-	-	3.0	4.9
110-150	-	-	-	7.3	21.2

Other physical data

Depth (cm)	Bulk density kg/dm³	pF 0 % v/v	pF 1.0 % v/v	pF 1.5 % v/v	pF 2.0 % v/v	pF 2.3 % v/v	pF 2.7 % v/v	pF 3.4 % v/v	pF 4.2 % v/v
10-35	1.290	49.7	46.9	41.4	30.5	24.0	17.7	5.9	4.3
110-140	1.350	44.5	42.0	36.6	27.8	24.1	19.8	13.9	11.5

Chemical data

Depth (cm)	pH H2O	pHKCl	EC 1: 2.5 dS/m	CaCO3 % w/w	C % w/w	N %	C / N	Exch. Acid cmol(c)/kg	Exch. Al cmol(c)/kg	Ca cmol(c)/kg	Mg cmol(c)/kg	K cmol(c)/kg	Na cmol(c)/kg	Sum Cations cmol(c)/kg
0-33	8.4	6.9	0.09	0.7	0.43	0.03	14	-	-	6.5	0.3	0.4	0.1	7.3
33-69	8.2	6.5	0.03	0.5	0.35	0.03	12	-	-	3.8	0.3	0.3	0.0	4.4
69-87	7.6	5.8	0.03	0.4	0.25	0.02	13	-	-	2.6	0.5	0.4	0.1	3.6
87-110	6.6	5.5	0.04	0.3	0.35	0.02	18	-	-	3.4	0.7	0.6	0.1	4.8
110-150	6.6	5.5	0.03	0.3	0.63	0.04	16	-	-	7.3	1.5	0.4	0.3	9.5

Depth (cm)	Base sat. %	CEC soil cmol(c)/kg	CEC clay cmol(c)/kg	CEC org cmol(c)/kg	ECEC cmol(c)/kg	Al sat. %	ESP %
0-33	183	4.0	118	1.4	-	-	3
33-69	113	3.9	108	1.4	-	-	0
69-87	106	3.4	106	1.1	-	-	3
87-110	104	4.6	94	1.4	-	-	2
110-150	103	9.2	-	2.2	-	-	3

Depth (cm)	pH NaF	P Retention %	ODOE	Al o % w/w	Si o % w/w	Fe d % w/w	Al d % w/w	Fe p % w/w	Al p % w/w	C p % w/w	Fe o % w/w
0-33	-	8	-	0.20	0.10	0.20	0.00	0.00	0.00	-	0.20
33-69	-	6	-	0.20	0.10	0.20	0.00	0.00	0.00	-	0.20
69-87	-	4	-	0.10	0.00	0.20	0.00	0.00	0.00	-	0.10
87-110	-	3	-	0.10	0.00	0.30	0.00	0.00	0.00	-	0.10
110-150	-	8	-	0.10	0.00	0.40	0.00	0.00	0.00	-	0.10

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-33	-	weak	-	-	weak	-	-	-	weak	-	-	-
33-69	-	weak	-	-	weak	-	-	-	weak	-	-	-
69-87	-	weak	-	-	weak	-	-	-	weak	-	-	-
87-110	-	weak	-	-	weak	-	-	-	weak	-	-	-
110-150	-	weak	-	-	very weak	-	-	-	weak	-	-	-

Profile description

Ap 0-33 cm	light brownish grey (10YR 6/2, dry) very dark greyish brown (10YR 3/2, moist)loamy sand,weakly coherent porous massive,very friable non sticky non plastic,many very fine interstitial pores and few interstitial pores,few charcoal inclusions and few pottery inclusions,few medium gravel pumice fragments,gradual wavy boundary to,
AC 33-69 cm	light brownish grey (10YR 6/2, dry) dark greyish brown (2.5Y 4/2, moist)loamy sand,weakly coherent porous massive,very friable non sticky non plastic,common fine distinct mottles (10 YR 6/2),many very fine interstitial pores and few tubular pores,few charcoal inclusions and few pottery inclusions,few medium gravel pumice fragments,clear wavy boundary to,
2C 69-87 cm	light grey (5Y 7/1, dry) greyish brown (2.5Y 5/2, moist)loamy coarse sand,weakly coherent porous massive,very friable non sticky non plastic,many very fine interstitial pores and common fine tubular pores,few medium gravel pumice fragments,abrupt wavy boundary to,
3Ab1 87-110 cm	very dark brown (10YR 2/2, moist)fine sandy loam,weakly coherent porous massive,very friable non sticky non plastic,many very fine interstitial pores and few tubular pores,frequent medium gravel pumice fragments,
3Ab2 110-150 cm	very dark brown (10YR 2/2, moist)loam,weakly coherent porous massive,friable slightly sticky slightly plastic,many very fine interstitial pores and common fine tubular pores,few medium gravel pumice fragments,

Kind 1 (parent material) ; Parker (eds), 1984	pyroclastic, unconsolidated
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	multiple ash layers
Soil Depth	200cm
Texture of parent material	sandy
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	slightly

Land use or vegetation in the immediate vicinity of the site	afforestation
Remarks on Land Use / Vegetation	VEGETATION: Eucalyptus, Chlica (Baccharin polyantha). Undergrowth consists of herbs and Kikuyu grass LANDUSE: Nearby maize

Altitude	2620m
Physiographic Unit	flat intermontane valley
Physiographic position of the site	slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	low hill
Slope	1%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-10cm
Depth to groundwater table	900cm
Kind of ground water table (USDA, 1979)	groundwater table observed
Moist From - To	10-205cm
Estimated permeability (class) of least permeable part of the profile	moderate

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

You are here

Reference soil Ecuador 13: Regosol

Characteristics

Reference soil EC013: Regosols

Classification