soils, soil processes & decomposition
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Soils, Soil Processes & Decomposition. Surface area increases as particle size decreases. Surface area influences ability to hold water and nutrients. Soil formation processes – Laterization Silicate rich parent material - PowerPoint PPT PresentationTRANSCRIPT
Soils, Soil Processes & Decomposition
Surface area increases as particle size decreases.Surface area influences ability to hold water and nutrients.
Soil formation processes – LaterizationSilicate rich parent material
Free polyphenols disperse clays & assist movement f/A->B Older, more intense weathering
Rapid decomposition of organics
Clays weather to Al and Fe oxides - SiO4 goneRed or Yellow color
Infertile, rapid and almost direct recycling; little nutrient storage
EntisolsUdipsamment
Entisols
Eudifluvent Lithic Ustorthent
Inceptisols
Typic Hydrandept Umbric Vitandrept
AlfisolsTypic Hapudalf
UltisolsTypic Hapudult
Oxisols Tropeptic Eutrorthox
Soil formation processes – Podsolization
Substrate usually well-drained quartz sand, acid, igneous
Transport of Fe and Al by soluble organic compounds. Plants from low N or low P soils produce polyphenols
E = intense eluviationB = illuviation of organic, Al, & Fe
Distribution world-wide, greatest in boreal zoneAlso in temperate and tropical zones on acid quartz sands
End point = acid, low nutrients Bleached E and Dark B with Organics, Fe and Al in B
Spodisols
Aeric HaplaquodTypic Haplorthod
Soil formation processes – Calcification
Drier sites; Calcium not leached out of soil profile
Gradient of decreasing precipitation matches thinner A horizon
A horizon high in organic content, mostly roots of grass
Often highly fertile
Climate/disturbance appears unsuitable for trees
Molliosols
Typic Haplaquol Typic Argiudoll
Typic Argiustol Typic Haplustol
Aridisols
Typic Haplargid Petrocalcic Paleargid
Typic Salorthid
HistisolsLimnic Medisaprist
Vertisols