a glimpse below… the soil food web teri c. balser, assistant professor, uw-madison...
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A glimpse below… A glimpse below… The soil food webThe soil food web
Teri C. Balser, Assistant Professor, [email protected]
What is soil biology?
What role does it play in soil quality?
Soil organisms are involved in nearly every aspect of soil
quality
Organic matter
Nitrate Leaching
SoilCommunity
Nutrient cycling
Structure/Aggregation
Humification
Decomposition
In order to understand how biology affects our soils - we need to understand a little about the
organisms who live there
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WaterWater
Soil particlesSoil particles Plant rootsPlant roots
Soil is a habitatSoil is a habitat
Soil is alive…Soil is alive…For example, in 1g of soil:>100,000,000 bacterial cells>100,000,000 bacterial cells>11,000 species of>11,000 species of bacteria bacteria Also fungi and larger animalsAlso fungi and larger animals
Who’s there?
Macrofauna: Soil ‘Engineers’
Termite
Snail
EarthwormEarthworm
Vole
Soil AnimalsSoil Animals
Centipede
Pseudoscorpion
1. Decomposition (shredding residues)
2. Mixing soil (aeration)
Decomposition rate of blue grama (Bouteloua gracilis)
Soil animals are important for
Who’s there?
Mesofauna: Soil predators, pathogens, herbivores
Soil mesofaunaSoil mesofauna
Nematodes
MitesMites
ProtozoaProtozoaQuickTime™ and a
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Soil mesofaunaSoil mesofauna
Nematodes
MitesMites
ProtozoaProtozoaQuickTime™ and a
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Soil mesofauna are important forSoil mesofauna are important for
1.1. Residue decompositionResidue decomposition
1.1. PredationPredation
1.1. PathogenesisPathogenesis
Microorganisms: Soil process controllers
Soil microorganisms Soil microorganisms
Fungi
BacteriaBacteria
Fungi
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Fungi
• Filamentous growth
What are the advantages of filamentous habit?
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Fungi
• Filamentous growth• Functionally critical!
-Wood degrading -Mycorrhizal association
•myco (fungus) +
rhiza (root)
(Symbiotic structure
formed by a fungus
plus a plant)
Source: Harrison et al 1999
Roots without mycorrhizae
Source: Harrison et al 1999
Roots with mycorrhizae
Bacteria
• Small, single celled ~2µm
What is the importance of small size?
Bacteria
• Small, single celled• Abundant
Bacteria
Fungi
ConventionalConventionaltillagetillage
No-tillNo-till
PrairiePrairie
ForestForest
Bacteria
• Small, single celled• Abundant• Diverse - taxonomically and functionally!
Diversity in soil is important for nitrogen cycling.
Relationship to soil quality?
Diversity may be important in response to management
Ecosystem Microbiology Laboratory, UW-Madison(www.ecosystem-microbiology.wisc.edu)
Teri C. [email protected]
USDA-CREES, NSF, Andrew W. Mellon Foundation, NASA
Lab members: Jessica Mentzer, Jenny Kao, Liang Chao, Nicole Craig, Lindsey Moritz, Meredith Schuman, Dr. David Bart, Dr. Daouda Ndaiye, Dr. Harry Read
THANK YOU!