THE SOIL FOOD WEB

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THE SOIL FOOD WEB
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Soil Biology and the Landscape
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The Soil Food Web
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Components of Soil Organic Matter
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Rhizosphere
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Microbial Biomass with Depth
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Seasonal Microbial Activity
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FOOD WEB SOIL HEALTH
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Biomass of Soil Organisms in Four Ecosystems
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Typical Numbers of Soil Organisms in Healthy
Ecosystems
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Methods for Measuring the Food Web
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Bacteria with fluorescent stain for counting
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A Complex Food Web
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Complexity of the Soil Food Web in Several
Ecosystems
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BACTERIA
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Bacteria
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Nitrogen-fixing Bacteria

• Nodules formed where Rhizobium bacteria infected
  soybean roots.

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Actinomycetes

• Bacterial cells that grow like fungal hyphae

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Bacteria vs. fungi
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FUNGI
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Fungi and Soil Quality

• 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
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Arbuscular Mycorrhizae (AM)
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MushroomsThe fruiting body of some fungi
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Mycorrhizal Fungi
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PROTOZOA
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PROTOZOA
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Flagellate
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Ciliate
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Amoebae
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Mineralization and Immobilization
Organisms consume other organisms and excrete
inorganic wastes.
Inorganic nutrients are usable by plants, and are
mobile in soil.
Organic nutrients are stored in soil organisms
and organic matter.
Organisms take up and retain nutrients as they
grow.
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Soil-Dwelling Vampires
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NEMATODES
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NEMATODES
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Predatory Nematode
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Root-feeding nematodes
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ARTHROPODS
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Mites and Biodiversity
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Types of Arthropods

• Shredders
• Predators
• Herbivores
• Fungal-feeders

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Shreddersmillipedes
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Predators (1)
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Predators (2)Pseudoscorpions
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Predators (4) Centipedes
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Predators (5)
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Herbivores
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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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What is in Your Soil?
Pitfall trap
Berlese funnel
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EARTHWORMS
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Earthworms bury litter
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Earthworm burrow
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Vertical burrows
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Earthworm casts
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Earthworm burrow opening
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Earthworm burrow opening
Midden pile
Burrow opening
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Reproduction