Answered: Question 1.2 i). Give a brief…

Applications and Investigations in Earth Science (9th Edition)

9th Edition

ISBN:9780134746241

Author:Edward J. Tarbuck, Frederick K. Lutgens, Dennis G. Tasa

Publisher:Edward J. Tarbuck, Frederick K. Lutgens, Dennis G. Tasa

Chapter1: The Study Of Minerals

Section: Chapter Questions

Problem 1LR

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Question 1.2

i). Give a brief description of the general environment in which each of the PNG’s Soil Order/Type is formed and found?

ii). List the type of land use for each Soil Order/Type in PNG and briefly provide reason(s) for this?

You will use the reference “Soils of Papua New Guinea by P. Bleeker, 1983” to answer part i) and ii).

Transcribed Image Text:3 Entisols Entisols have no profile development with the possible exception of a thin, dark or light coloured A horizon. They are very young soils occurring mainly on recently deposited alluvium, or are found in hilly or mountainous terrain where soil erosion has kept pace with soil formation. Entisols have five suborders, four of which have been identified in Papua New Guinea. Aquents are the wet Entisols which are characterised by strong gleying at or close to the surface. Long periods of high water tables cause reduced conditions owing to a lack of oxygen, which is reflected in their grey and blue colours. Fluvents are basically the better drained counterparts of the Aquents occurring on recently deposited river sediments. They are mostly olive, olive brown, or brownish coloured (mostly in 2.5Y hues) and are well drained although some indication of gleying and/or mottling below 50 cm depth may be present. By definition the organic carbon content of the Fluvents decreases irregularly with depth or remains above 0.2 per cent to a depth of 125 cm. This is caused by stratification. Fluvents must have a texture finer than loamy sand to distinguish them from the Psamments which are coarse textured soils occurring commonly along the coast on beach sands or, less commonly, further inland on coarse sedimentary deposits such as sandstone. Entisols developed primarily on recent erosional surfaces are called Orthents. They are very common in mountainous terrain having slopes of more than 30°, but may also be found on alluvial deposits. SULFAQUENTS Morphology Because these soils only become strongly acidified upon aeration, they have never been positively identified in Papua New Guinea. Nevertheless they can be expected to occur extensively in natural conditions in coastal areas on marine and estuarine deposits, which have specific type(s) of mangrove vegetation (Plates 3.1 and 3.2). Sulfaquents are continuously waterlogged soils, consisting of thick mostly silt or clay rich sedimentary layers with a high content of finely dispersed organic matter commonly intermixed with thin organic layers. They have a neutral to alkaline soil reaction. Upon drying,