Soil Organisms and Roles
Power point taken and modified from Tuesday Desaulnier’s Soil Bio. PPt
Soil BiologySoil Biology
Who is down Who is down there and what there and what do they dodo they do
Sun
Humus
Producers
ConsumersDecomposers
air water
soil
Important Groups of Soil OrganismsImportant Groups of Soil Organisms
• MacrofloraMacroflora
• MicrofloraMicroflora
• MacrofaunaMacrofauna
Vascular plantsVascular plants, mosses, mosses
algae, bacteria, and fungialgae, bacteria, and fungi
Vertebrates, arthropods, earthworms, Vertebrates, arthropods, earthworms, snails… snails…
• MesofaunaMesofauna
• MicrofaunaMicrofauna
smaller arthropods and wormssmaller arthropods and worms
Nematodes, protzoaNematodes, protzoa
Size/type classSize/type class e.g. and functional group/energy acquisitione.g. and functional group/energy acquisition
Soil Animals – micro, meso, macro
BacteriaMicroflora
Microflora
Nematodes
Protozoa
Microfauna
20-200 kg/ha!20-200 kg/ha!
Mites
Springtails
Mesofauna
Other invertebrates
Mesofauna
Worms
Voles!
Macrofauna
A cup of soil containsA cup of soil contains......
BacteriaBacteria
Fungi*Fungi*
ProtozoaProtozoa
NematodesNematodes
ArthropodsArthropods
EarthwormsEarthworms
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microfaunamicrofauna
macro- and macro- and mesofaunamesofauna
200 billion200 billion
100,000 meters
20 million20 million
100,000100,000
50,00050,000<1<1
Microflora, Microflora, or “microbes”or “microbes”
B – BacteriaA – ActinomycetesMy – MycorrhizaeH – Saprophitic fungusN – NematodeCP – Ciliate protozoaFP – Flagellate protozoaM – Mite
< 1mm
1/10 mm
Aggregates held together by:
1. Fungal hyphae2. Bacterial “glues”3. Organic matter
sand
silt
hyphaeclay
bacteria
Complex, mutually beneficial Complex, mutually beneficial relationshipsrelationships
fungi
bacteria
Earthworm middenEarthworm midden
Earthworms Earthworms – (have gizzards!)– (have gizzards!)
• Probably the most important component of Probably the most important component of soil fauna (not in acid soils, not in very dry soil fauna (not in acid soils, not in very dry soils)soils)
• Eat OM & pass as much as 30 tons/ha of Eat OM & pass as much as 30 tons/ha of soil through their bodies (mixing horizons) soil through their bodies (mixing horizons) each yeareach year
• Promote good soil structure and aerationPromote good soil structure and aeration
Sun
Humus
Producers
ConsumersDecomposers
air water
soil
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