Reference soil New Zealand 03: Andosol

NZ003

Andosols occur throughout the world where volcanic activity is common, especially in the circum-Pacific region and along the mid-Atlantic Ridge.

Characteristics

Soils with a vitric or andic horizon (slightly to moderately weathered horizons in pyroclastic deposits dominated by short-range-order minerals, notably allophane and imogolite) starting within 25 cm from the soil surface. In addition, they may have a histic, fulvic, melanic, mollic, umbric, ochric, duric, or cambic horizon. Other diagnostic horizons (unless buried deeper than 50 cm by volcanic deposits) are absent.

Distribution of Andosols (rough estimation supplied by soilgrids)

Reference soil NZ003: Andosols

LAND USE: dayring land supporting ryegrass-white clover pastures. Original vegetation: fern, tutu, scrub

Classification

WRB 1998

Dystri-Silic- Andosol

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Haplic Andosol

Ochric Andosol

Local classification:	Moderately leached central yellow-bron soil; Egmont black loam

Other classification

USDA-NRCS (1999)	Typic Hapludand
USDA-SCS (1975)	Typic Dystrandept udic medial mixed mesic

Depth1	70cm
Kind 1 (parent material) ; Parker (eds), 1984	acidic ash
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	andasitic ash (ash of Mt. Egmont)
Texture of parent material (second entry)	loamy
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	dairying
Remarks on Land Use / Vegetation	VEGETATION: cocksfoot, sweet vernal, ryegrass pasture
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	90m
Physiographic Unit	flat part
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	volcano
Slope	0%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Drainage class ; FAO (2006) - Guidelines for soil description	well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-100cm
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
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

Ah 0-20 cm	black (10YR 2/1, moist)loam,moderate nutty subangular blocky,friable,many roots,clear irregular boundary to,
Bw 20-46 cm	(10YR 4.5/2.5, moist)loam slightly gravelly,very weak medium nutty subangular blocky parting to very weak medium crumb,very friable,few roots,few fine gravel weathered pumice fragments,clear wavy boundary to,
46-67 cm	yellowish brown (10YR 5/4, moist)silt loam slightly gravelly,porous massive to weak fine subangular blocky,firm,few roots,few fine gravel weathered pumice fragments,gradual smooth boundary to,
C 67-100 cm	dark yellowish brown (10YR 4/4, moist)silt loam slightly gravelly,porous massive,very firm moderately smeary,few roots,few fine gravel weathered pumice fragments,

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Reference soil New Zealand 03: Andosol

Characteristics

Reference soil NZ003: Andosols

Classification