Agriculture Reference
In-Depth Information
In this general framework, also the integrated use of compost combined with
solarization could be very interesting. Gamliel and Stapleton (
1993
) showed the
positive effects gained by integration of chicken compost amendment and soil so-
larization on lettuce growth and suppressed infections by
Pythium ultimun
. Simi-
larly, Choi et al. (
2007
) showed the potential of spent mushroom sawdust compost
used in combination with calcium cyanamide and solarization, in the control of
Fusarium basal stem rot of the cactus
Hylocereus trigonus
. Compost complements
solarization efficacy by preservation of soil quality from heat damage and inducing
significant changes in microbial community structure. This was seen with DGGE
profiles that showed how mature household compost incited shift in solarized soils
towards a community with enhanced antagonism against
R. solanacearum
(Schön-
feld et al.
2003
).
8.6
Compost as Source of Plant Protectants
Compost suppressivity can be fully exploited as source of suppressive biotic or abi-
otic agents that can be isolated from composts and used directly in protecting plants
(Fig.
8.4
). In this way, the composts became a suitable source of new products
that, after extraction from the original matrix, will follow a completely independent
path of development and application. Essentially, from suppressive composts can
be derivate of two types of plant protectants: biological control agents and natural
compounds.
8.6.1
Microbial Antagonists
Compost is a suitable source of microbial antagonists which can be used singularly
or in consortia to implement plant disease management (Fig.
8.5
). The research in
the field of biological control of plant pathogens, then, take advantage of compost
suppressive properties that origin from the biotic components. A number of ex-
amples shows how the application of a screening strategy to a suppressive compost-
derived micro-flora, can lead to the isolation of the best individuals exhibiting the
desired characteristics. Composted urban organic and yard wastes, for example,
has been used as source for antagonists belonging to fungi, bacteria and oomycetes
characterized against different pathogen species (Pugliese et al.
2010
). In particular,
in this last situation, strains of
Trichoderma
and of non-pathogenic
Fusarium
sp.
showing antagonistic activity against some soil borne pathogens, such as
R. solani
and
F. oxysporum
f. sp.
basilici
, respectively, were remarked (Pugliese et al.
2008
).
Compost water extracts were found to contain
Bacillus
sp.,
Micrococcus
sp.,
Staph-
ylococcus
sp. and
Corynebacterium
sp. and the fungi
Aspergillus
sp.,
Rhizopus
sp.,
Drechslera
sp. and various species actinomycetes responsible for antagonistic ac-
tivity (El-Masry et al.
2002
).
