15_SoilAndMycorrhizae

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Transcript 15_SoilAndMycorrhizae

Bacterial vs Fungal
• Grass – usually bacterially dominated soil
• Forest – fungally dominated
• Ideal orchard soil = fungal dominance 10 x
higher than bacteria – a ratio that defines
forest-edge ecology
Shifting the ratio
• Bacteria utilize simple organic compounds like
root secretions and fresh plant residue
• Fungi respond best to surface decomposition
while bacteria prefer soil disturbance.
• Fungi use more complex compounds like
cellulose, lignins and soil humus.
• Bulky organic material as mulch –build soil
from top down as does nature
Amazing Mycorrhizae!
•Symbiotic relationship with roots
•Over 90% of plants form relationship
•Absorptive area of roots massively increased
•Nutrients can be transported up to 40m
•C-rich sugars traded with nutrients and water
•Produce glomalin (gives soil it’s tilth), growth
factors and anti-biotics
•Can even protect root from pests
•Trees linked to other trees & plants
Mycorrizal fungus on root
Mycorriza on root hair
Root-eating nematode captured by
fungal hyphae!!!