Soil Biology and EcologyUnit 2.3 | 7- Roots
a) Root environment
b) Root form
c) Root structure
d) Nutrition
e) Exudates
f) Variations
g) Management effects
- Soil organisms
a) Bacteria
b) Fungi
c) Protozoans
d) Nematodes
e) Microarthropods
f) Rhizosphere succession
g) Examples
H. Management Effects on Soil Ecosystems
- No-tillage or reduced-tillage cropping systems
a) Organic litter is retained on the soil surface
b) Physical disturbance is minimized
c) Surface soil stays cooler and moister
d) More surface organic matter is available as food substrate
e) Ratio of fungi to bacteria increases over time
f) Earthworms and arthropods become more plentiful
- Rotations
a) Monocultures and clean cultivation
b) Complex rotations
c) Multiculture
- Biocides
a) Effects vary
b) High levels of pesticide use generally reduce food web complexity
c) Predator-release phenomenon
d) Earthworms
- Food web structures
a) Fungi/bacteria ratio
b) Dominant microbe influences other trophic levels
- Assessment of fertility needs
a) Measures of available nitrogen