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• 4 Soil profile and soil suitability

• 4.1 Introduction

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•  What are suitable decomposition conditions?

  Moist, neutral-basic, easily decomposable litter.

• What effect do aromatic compounds have on the decomposition rate?

  They slow it down.

• What are bad conditions for earthworms?

  1. Drought
  2. Little aeration
  3. Scarce supply of easily decomposable litter
  4. Acid soil

• What are the caracteristics of fungi?

  Largely occur in the litter layger where they invade organic matter though their tread-like mycelium and decompose it in place. Need humidity.
  
  Other soil fauna feed on their mycelium. Many worms = little fungi, little litter.

• What are caracteristics of bacteria?

  Mineralization.
  They are not mobile and thus depend on other fauna (earthworms) to move they through the soil.

• What is the main role of larger soil animals in the soil?

  Bioturbation (mixing of litter and mineral material) and they determine whether litte ris present at the surface.

• What is the main role of smaller soil animals and decomposing micro-organisms in the soil?

  Their impact is more local and their activities do not result in bioturbation.

• What are the first 4 levels of the soil trophic system?

  1. Primary producers (green plants)
  2. Primary consumers (eat green plants litter)
  3. Predators and micobial feeders
  4. Predators of predators

• How does the soil profile look when litter accumulates on top?

  Clear horizon differentiation with sharp horizon boundaries.

• How does the soil profile look when the balance is towards decomposition?

  Limited contrasts between horizons and very gradual boundaries as a result of rapid homogenisation.