SQ 1 Soil Biology Primer

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(SQ 1) Soil Biology Primer
Components of Soil Organic Matter
Photos taken from the NRCS Soil Quality Institute
website Source Soil Biology Primer
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Soil Biology and the Landscape
Rhizosphere
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Typical Numbers of Soil Organisms in Healthy
Ecosystems
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Microbial Biomass with Depth
Seasonal Microbial Activity
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Complexity of the Soil Food Web in Several
Ecosystems
Mineralization and Immobilization
Organic nutrients are stored in soil organisms
and organic matter.
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Bacteria with fluorescent stain for counting
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Nitrogen-fixing Bacteria
Actinomycetes (decomposers)

• Nodules formed where Rhizobium bacteria infected
  soybean roots.

Bacterial cells that grow like fungal hyphae
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FUNGI
MushroomsThe fruiting body of some fungi
- Decompose carbon compounds - Improve OM
accumulation - Retain nutrients in the soil -
Bind soil particles - Food for the rest of the
food web - Mycorrhizal fungi - Compete with plant
pathogens
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Mycorrhizae
Tree root
Fungal hyphae
Mycorrhizal structure
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Ectomycorrhizae
Arbuscular Mycorrhizae (AM)
Mycorrhizal Fungi
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Springtails (fungal feeders)

• Abundant in many soils.
• Feed on some disease-causing fungi.
• Jump by slamming their tail down.

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PROTOZOA
Ciliate
Soil-Dwelling Vampires (amoebae that eat fungi)
Flagellate
Amoebae
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NEMATODES
Lesion-Feeding Nematode
Root-Feeding Nematode
Predatory Nematode
Bacterial-Feeding Nematode
Fungal-Feeding Nematode
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Herbivores
(Symphylan)
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FOOD WEB SOIL HEALTH
Mites shredding a leaf
(Predatory Mite)
Mites and Biodiversity
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Shreddersmillipedes
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PredatorsPseudoscorpions
Rugose Harvester Ants
Wolf Spider
Centipedes
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EARTHWORMS
Earthworm burrow
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Vertical burrows
Midden pile
Earthworms bury litter
Burrow opening
Earthworm casts
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