Term
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Definition
Content 1-5 % of A horizon
• Heterogeneous, made up of material at different stages of
decomposition (dead plants, animals and excretory products,
soil flora, end products of decomposition)
• High CEC, CEC pH-dependent, most important in sandy soils
• Capable of chelating metals |
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Term
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Definition
Chelation of metals, may improve most micronutrient transport and availability
• Micronutrients mineralize from soil OM |
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Term
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Definition
• Stabilizes soil structure, increases available water
• Source of nutrients (Particularly nitrogen)
• Absorbs some organic solutes (e.g., herbicides) |
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Term
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Definition
a balance between rates of
addition of organic
materials and rates of loss |
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Term
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Definition
• Increase with increasing yields
• Decrease with removal of increasing amount of
crop residue
• Increase with deposition of eroded soils
• Increase with addition of organic materials |
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Term
Factors Influencing the Rate of
Decomposition of Organic matter |
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Definition
Type of organic matter
• Size of organic matter
• Amount of mixing in the soil
• Temperature
• Moisture
• Oxygen status (redox potential)
• Soil pH
• Nutrient availability |
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Term
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Definition
Increase with rates of decomposition
• Aeration: decreased aeration, increased decomposition
by anaerobic organisms, decreased rates of
decomposition
• Water content: increased decomposition with increasing
water content until aeration becomes limiting
temp: increase with temp (in range commonly
encountered in field)
• pH
• composition of residues (type of C, N content)
• Increase with increased erosion |
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Term
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Definition
•Heterotrophs carbon from organic material
•Autotrophs carbon from CO2 |
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Term
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Definition
•Vertebrates (Groundhog)
•Arthropods (insects)
•Annelida (earthworms)
•Mollusca (slugs and snails) |
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Term
what organism can:
Burrowing will improve porosity
Improve aeration and water flow
(preferential flow )
Mixing of organic matter |
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Definition
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Term
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Definition
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Term
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Definition
Nematodes
protozoa
Actinomycetes bacteria |
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Term
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Definition
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Term
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Definition
algae-• Eutrophication
• Autotrophic
fungi-Decomposition and
stabilization of soil
structure
• Mycorrhizae |
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Term
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Definition
bacteria like
fugal attributes
heterotrophic |
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Term
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Definition
important in nearly all soil organic prosses
broad of enzyme activity |
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