Australian Agriculture Assessment 2001
Australian agriculture assessment 2001
National Land and Water Resources Audit, 2001
Appendix 3 - Ferrosols
These very permeable clayey soils have relatively high contents of free iron oxide (>5%Fe) and no strong texture contrast between the A and B horizons. The most common forms have strong polyhedral or blocky compound structure resulting in very favourable physical properties. The majority of Ferrosols are red in colour, with fewer brown forms, and usually exhibit subplastic properties.
Red Ferrosols
Although Red Ferrosols have a relatively restricted range in morphological features, they may differ widely in their chemistry. The first typical example given below is that of a Haplic, Mesotrophic, Red Ferrosol. These soils have a moderate base status (see below), pH in the B horizon is greater than 5.5 and the soils lack dark or humose A1 horizons.
Environment
Distribution: Widespread but relatively small occurrences of Haplic, Red Ferrosols occur mainly in subcoastal eastern Australia from north Queensland to Tasmania and in the Kimberley region of north-west Australia.
Climate: Mean annual rainfall ranges from 500 mm to over 1000 mm. Mesotrophic forms are less common at the extreme ends of this range.
Parent materials or substrate: Almost universally derived from basic igneous rocks such as basalt and dolerite, less extensively on ultrabasics such as serpentinite, and from derived alluvium.
Landform: Undulating plains and plateaux and some high, hilly lands.
Native vegetation: Rainfall dependent, ranging from open woodland to eucalypt forest and rainforests. Most areas are now cleared.
Land use
Haplic, Red Ferrosols are used for a wide variety of crops including sugar cane and tropical tree crops in south-central Queensland, grain crops (maize and peanuts) in north and south Queensland, vegetables (particularly potatoes) from north Queensland to Tasmania, improved pastures for dairying and horticultural crops over a wide latitude range. Cattle grazing of native pastures is the sole form of land use in the drier regions of north Queensland and the Kimberley region.
Common variants
Haplic, Red Ferrosols vary widely in base status with occasional soils calcareous in lower B or BC horizons. Dark A1 horizons tend to be masked by the high iron contents and hence are uncommon.
Nomenclature
Also known as Krasnozems and Euchrozems.
Soil qualities
Water availability: High to very high (250 mm).
Drainage: Well drained soils. Runoff may occur under high intensity rainfall.
Aeration: Short term saturation may occur under prolonged, heavy rainfall on compacted soil.
Physical root limitations: No serious limitation to root growth unless the soil is compacted.
Erosion hazard: Often serious on slopes where compaction of surface soil layers leads to low infiltration.
Nutrient availability: Cultivated or eroded forms show deficiencies in nitrogen and phosphorus, most show high phosphorus sorption due to high free iron oxide.
Toxicities: Aluminium toxicity may be induced by high nitrogen fertiliser application causing strong acidity.
Workability: Compaction caused by heavy machinery on wet soils will lead to poor workability.
Typical profile
Near Bundaberg, Queensland. |
Soil description of a typical profileA1 0 - 0.20 m Dark reddish brown (5YR 3/3) light clay; moderate polyhedral structure; dry, firm consistence; diffuse boundary to: B21 0.20 - 0.90 m Reddish brown (2.5YR 3/4) light clay; strong polyhedral structure; moist, soft consistence; diffuse boundary to: B22 0.90 - 1.80 m Reddish brown (2.5YR 3/5) light clay; moderate blocky structure; moist, soft consistence; diffuse boundary to: B23 1.80 - 2.10 m Yellowish red (5YR 4/6) light clay with faint brownish mottles; slight amount of basalt gravel; moist, very soft consistence. BC 2.10 m+ Mottled light clay with increasing weathered basalt. |
Laboratory data for the typical profile
Acknowledgment
Photo from CSIRO Land and Water. Soil description and laboratory data from Stace et al. (1968), p. 305, Profile B.
The soil described and discussed below is a Acidic, Mesotrophic, Red Ferrosol of moderate base status but is strongly acid (pH <5.5) in the B2 horizon and lacks a dark or humose A1 horizon.
Environment
Distribution: Almost entirely determined by the occurrence of basalt and high rainfall. The acidic soils occur mainly on the wetter east coastal areas of Australia and northern Tasmania.
Climate: Mean annual rainfall range approximately 1000 mm to over 3000 mm in near coastal north Queensland.
Parent materials or substrate: Basic igneous rocks (particularly basalt) and derived alluvium.
Landform: General range from near level plains to undulating tablelands and mountainous areas.
Native vegetation: Tropical/ temperate rainforest in high rainfall areas. Eucalypt forest elsewhere.
Land use
Sugar cane is grown on these acidic soils in coastal north Queensland together with bananas and improved pastures for dairy and beef cattle. In the Lismore district of New South Wales intensive horticulture (mainly tree crops) is a feature. In the temperate subcoastal regions of south-east Australia and Tasmania vegetables (particularly potatoes) and improved pastures for dairying are grown.
Common variants
Dystrophic forms with very low base status generally occur in higher rainfall areas and may have a humose A1 horizon.
Nomenclature
Also known as Krasnozems.
Soil qualities
Water availability: Generally high to very high (> 250 mm).
Drainage: Very well drained with a high infiltration rate due to their strongly developed and stable structure.
Aeration: These structured soils are generally well aerated in profiles not affected by compaction.
Physical root limitations: No serious limitation to root growth unless the soil is compacted.
Erosion hazard: High under high intensity rainfall. Compaction may lead to greater runoff and erosion particularly when vegetation cover is minimal.
Nutrient availability: The nutrient status of these strongly leached soils is usually low below the surface horizon. Strong phosphorus sorption due to high free iron oxide and high pH buffering capacity are a feature.
Toxicities: May suffer from acidification induced by high nitrogen fertilizer application.
Workability: Compaction occurs if over cultivated or tilled when the soil is wetter than its plastic limit.
Acknowledgment
Photo, soil description and laboratory data from Department of Natural Resources and Environment, Victoria. Site GP 15.
Typical profile
Ellinbank district, West Gippsland, Victoria. |
Soil description of a typical profileA1 0 - 0.30 m Dark brown (7YR 3/4) fine sandy clay loam (subplastic); weak coarse blocky parting to very fine polyhedral structure; moist, soft consistence; gradual boundary to: B21 0.30 - 0.50 m Yellowish red (5YR 4/6) clay loam (subplastic); moderate medium blocky parting to strong fine blocky structure; moist, soft consistence; gradual boundary to: B22 0.50 - 0.80 m Red (2.5YR 5/8) light clay (subplastic); moderate medium blocky parting to strong fine blocky structure; gradual boundary to: B23 0.80 - 1.00 m Yellowish red (5YR 5/8) light clay (subplastic); weak coarse blocky parting to strong fine polyhedral structure; clear boundary to: B24 1.00 m+ Yellowish red (5YR 5/8) light clay (subplastic); moderate coarse polyhedral structure; 30% clay/ iron oxide nodules (10 - 20 mm in size). |
Laboratory data for the typical profile
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