Agriculture Reference
In-Depth Information
Interactions
with microflora for digestion
of complex organic molecules
ECOSYSTEM ENGINEERS
LITTER TRANSFORMERS
MICROPREDATORS
MICROFLORA
Formation of biogenic structures
FIGURE 8.1
Relationships of earthworms and other soil Ñecosystem engineersÒ with other soil biological
components. Earthworms partly influence the occurrence and activity of other soil organisms because they
create large structures that may persist over significant periods and affect the environment. (From Lavelle
1997. With permission.)
PEDOGENESIS
SOIL STRUCTURE
SOM DYNAMICS
AGGREGATION
HUMIFICATION
MINERALIZATION
EARTHWORM
CASTING
BURROWING
DIGESTION
MICROBIAL
ACTIVITY
MYCORRHIZAL
INFECTION
FIGURE 8.2
Effects of earthworm activities on soil processes operating at different scales.
scale at which SOM dynamics and nutrient cycling are generally studied. One spectacular result of
this smaller-scale approach is a huge discrepancy between the great importance that pedobiologists
attribute to earthworms as regulators of soil physical structure and SOM dynamics and the absence
of any representation of earthworm activities in simulation models that describe SOM dynamics at
