Reference soil Venezuela 01: Plinthic Acrisol

VE001

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil VE001: Plinthic Acrisols

'Modules' have been constructed some years ago in the LLanos area. A module consist of an area of about 10 to 20.000 ha surrounded by low diques(height of about 2 to 3 metrs). Through several outlets the yearly flooding is controlled. The main objective of the module is to extent the flooding time of an area with a preset flooding height. * The grass species will change for better palatable spp. due to an improved flooding regime. Sealing of the soil will not occur under grass vegetation. When the soil is cultivated it will seal severely. The microrelief consists out of a dense pattern of small micro mounds of an height of about 15 to 20cm. The micro mounds are probably caused by soil fauna(worms?) and fixed by the grasses. The soil consists out of 2 different main horizons, the light colo ured and lightì textured very porous horizon from 0 to about 45cm(A+AB+E) and the clayey compact strongly mottled subsoil from 45 to 150+(Btg1+Btg2). The coarse prismatic elements of the B-horizon have a grey colour at the outer side and are strongly reddish mottled in the inner side of the structure element.

- cm	argillic B horizon
-	albic material
-	plinthite

Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	Pleistocene alluvium
Soil Depth	125cm

Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	land improvements - not specified
Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	Flooding influences spp composition*
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	medium tall grassland

Altitude	400m
Physiographic Unit	low extensive basin area
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	stagnant alluvial plain
Slope	0%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Lower limit of a slow permeable or stagnating layer in the profile	0cm
Drainage class ; FAO (2006) - Guidelines for soil description	poor
Dry From - To	0-50cm
Flooding frequency (FAO, 1986)	yearly
Nature of flood water	still or stagnant
(Estimated) maximum (lower) depth to groundwater table	0cm
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	flooded
(Estimated) minimum (upper) depth to groundwater table	10cm
Moist From - To	50-150cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	ponded
Upper limit of a slow permeable or stagnating layer in the profile	80cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Microrelief Height: variation in height	20
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	knobs
Microrelief pattern	isolated
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

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Reference soil Venezuela 01: Plinthic Acrisol

Reference soil VE001: Plinthic Acrisols

Classification