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(a)
Tylenchus
(b)
Rhabditis
(c)
Aphelenchidae
(d)
Anguinidae
Figure 5.4
Two-dimensional NMDS ordination based on (a) and (b) nematode genus composition
(44 genera, 2-D stress = 0.185) or (c) and (d) family composition (29 families, 2-D stress = 0.155) in 16
plots of biodynamic, bioorganic, conventional with farmyard manure and conventional only with
mineral fertilizer (stockless farming) farming systems (see
Table 5.1
). Bubble sizes are scaled accord-
ing to the data range and superimposed based on densities of (a)
Tylenchus
sp. (data range = 0-3 ind
g soil dw
−1
), (b)
Rhabditis
sp. (0-3 ind g soil dw
−1
), (c) Aphelenchidae (0-0.5 ind g soil dw
−1
), and (d)
Anguinidae (0-0.8 ind g soil dw
−1
).
lower abundances in conventionally managed soils (
Figure 5.4d
)
. At the level of trophic
groups, differences between farming systems were still significant (
R
= 0.291;
P
= 0.019),
but only the trophic group composition in BIODYN differed significantly from both con-
ventionally managed systems. Trophic group composition in BIOORG soils only tended to
differ from CONMIN. Hyphal and plant feeders primarily contributed to these differences
as this functional group was always more abundant in organically managed systems.
Enchytraeid communities did not differ significantly between farming systems,
independent of whether analyzed on species (
R
= 0.047;
P
= 0.322) or genus (
R
= 0.102;
P
= 0.204) level. The community composition of spiders also did not differ significantly
between farming systems at the species (
R
= 0.177;
P
= 0.113), family (
R
= 0.052;
P
= 0.232),
or functional group (
R
= 0.081;
P
= 0.182) level. The same result was observed for carabid
beetles, not showing a significant difference between farming systems if analyzed at spe-
cies (
R
= 0.001;
P
= 0.478), family (
R
= −0.055;
P
= 0.678), or functional group level based on
either wing morphology (
R
= −0.102;
P
= 0.844) or trophic group (
R
= 0.017;
P
= 0.388).
Multivariate patterns in community composition of some soil organisms were closely
related to patterns in soil properties (pH, SWC, C
org
, and N
tot
) as
the community composi-
tion of nematodes based on genus or family levels resembled plot-specific soil properties
(
Figure 5.5
)
. Nematode functional group composition and microbial community structure
based on FA profiles or biomarker groups still resembled multivariate patterns for soil prop-
erties. The observed patterns in community composition of enchytraeids, carabids, and spi-
ders were less closely related to soil properties. In carabids, community composition based
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