Desert Soils

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7 Citations (Scopus)

Abstract

In contrast to wetter areas, where soil mantles of pedogenically altered decomposed bedrock cover most or all of the landscape, the surfaces of deserts may be only patchily covered with soil. The surface over many desert uplands is formed of outcropping bedrock, and in lower-lying areas there may be a cover of aeolian or fluvial sediments so little modified that it hardly amounts to ‘soil’ by any common definition (e.g. many fall into the entisol order of the US system of taxonomy). In semi-arid areas, the effects of pedogenesis become more apparent, and a richer array of soil types has been described from these environments. Factors that contribute to climatic gradients in soil properties include various climatic factors such as rainfall and temperature, and also increasing biomass and larger accessions of organic detritus in humid environments. Rainfall in drylands tends to decline with distance from the ocean. Mean rates of rainfall decline are often around 1 mm/km, but the trend is really exponential in form and regressions show that the rainfall declines by 50% over distances of about 400 km. In addition to driving a decrease in plant cover, this pattern of diminishing rainfall results in less intense leaching of dryland soils, and consequently quite steep regional gradients in dryland soil properties occur. In areas of extensive forest, rainfall decline with distance inland is much less evident owing to the biotic recycling of precipitation, and biomass and soil properties vary less steeply.
Original languageEnglish
Title of host publicationArid Zone Geomorphology
Subtitle of host publicationProcess, Form and Change in Drylands
EditorsDavid S G Thomas
Place of PublicationChichester UK
PublisherJohn Wiley & Sons
Chapter7
Pages101-129
Number of pages29
Edition3
ISBN (Electronic)9780470710777
ISBN (Print)9780470519080, 9780470519097
DOIs
Publication statusPublished - 13 Mar 2011

Keywords

  • Behaviour and environments of BSCs - on north- and south-facing dune flanks in Hallamish dune field, Israel
  • Biological soil crusts' effects - on infiltration and overland flow
  • Desert soils
  • Dryland soil surfaces, properties - different from deeper subsurface, raindrop energy having no effects
  • Drylands, and soil infiltrability - locally, very low
  • Major soil orders - of arid and semi-arid regions
  • Marked differences in hydrologic role of soils - in drylands and in humid zones
  • Nutrient status, or desert soil cropping potential
  • Rock and soil nich classification - inhabited by desert microorganisms
  • Spatial heterogeneity of desert soils

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