Soil Flora

Soil microbial populations consist of autotrophs, decomposers, and mutualists. Their distribution is influenced by soil conditions and plant interactions.

 

A. Bacteria:

  • Most abundant soil microorganisms.
  • Classified as autochthonous (indigenous) and zymogenous (fermentation) types.
  • Major genera: Arthrobacter, Bacillus, Pseudomonas, Agrobacterium, Alcaligens, Flavobacterium.

 

B. Actinomycetes:

  • Gram-positive bacteria with filamentous growth.
  • Dominant genera: Streptomyces, Micromonospora, Nocardia.
  • Play a role in decomposition and antibiotic production.

 

C. Fungi:

  • Second most abundant microflora after bacteria and actinomycetes.
  • Common genera: Penicillium, Aspergillus, Fusarium.
  • Significant for decomposition, mycorrhizal associations, and disease suppression.

 

D. Archaea:

  • Previously classified as archaebacteria, reclassified based on molecular studies.
  • Found in extreme environments and cropland soils.
  • Important in methane production and ammonia oxidation.

 

E. Algae:

  • Less abundant but present in moist, well-lit soils.
  • Groups: Cyanophyceae (blue-green algae), Chlorophyceae (green algae), Xanthophyceae (yellow-green algae), Bacillariaceae (diatoms).
  • Found mostly in the top 10 cm of soil.
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