Agriculture Reference
In-Depth Information
Table 3.1. Designations of Different Types of Organisms Common in Soil
Organism
Characteristic
Aerobic
Lives in the presence of oxygen and carries out oxidation reactions
using oxygen as an electron acceptor
Anaerobic
Lives in the absence of oxygen and uses electron acceptors, other
than oxygen (i.e., nitrogen and carbon)
Heterotrophic
Requires preformed organic compounds for energy and cell
production
Autotrophic
Obtains energy from oxidation of inorganic ions and obtains carbon
from carbon dioxide
Thermophillic
Grows at elevated temperatures; may be any of the types of
organisms listed above (>40°C and £100°C)
a
Mesophilic
Grows at moderate temperatures; may be any of the types of
organisms listed above (>5°C and <40°C)
Cyrophillic
Grows at low temperatures; may be any of the above types of
organisms listed above (<5°C)
a
a
Organisms have been reported as growing beyond these temperature ranges.
Cocci
Bacteria
Actinomycetes
Fungi
Figure 3.5.
Common soil microorganisms (not drawn to absolute or relative scale).
versatile in the reactions they carry out and in well-drained soils they inhabit
aerobic (oxidizing), anaerobic (reducing), and microaerophilic zones in soil
peds. Microaerophilic zones are those with low concentrations of oxygen. In
Figure 3.7 the area marked as
A
will be anaerobic, while the area just inside
the mouths of the pore but before the inner water containing areas will be
