Environmental Engineering Reference
In-Depth Information
application (Gianinazzi and Vosátka
2004
). The
critical factor that determines the inoculum effi -
ciency is the dosage and the time of inoculation.
Although, theoretically, a single propagule of
AM fungi is suffi cient to initiate mycorrhization,
the colonization process in such cases is very
slow to be of agronomic interest. About 1-2 kg of
soil inoculum (with 5,000-10,000 propagules)
per m
2
of seedbed could be an appropriate appli-
cation rate. However, the application rate for
each crop species has to be standardized for a
given set of environmental conditions
(Muthukumar and Udaiyan
2003
). The time of
inoculation is also important, and in general, the
earlier the inoculation, the greater the benefi t to
the plant (Barea et al.
1993
).
association are most widely to occur when
mycorrhizal-dependent crop species are raised on
substrates with low P levels. Therefore, it is
important to determine the mycorrhizal depen-
dency of the crops grown in a region and to select
those which could respond to AM inoculation.
Screening for selection of an effi cient crop-AM
fungal combination should be undertaken.
Research should be intensifi ed in the direction of
manipulating AM fungi in the indigenous AM
fungal community to achieve maximum crop
productivity. The optimization of agronomic
practices, reducing fertilizer input and use of
cheap source of fertilizer (rock phosphate,
organic manures) should be investigated. Top pri-
ority should be given to the development of new
technologies for rapid and large-scale quality
inoculum production. Further, one of the main
tasks in AM research is to raise awareness in the
growers' mind about the potentials of AM tech-
nology in sustainable crop production and soil
conservation.
6.2
Inoculation Methods
The aim of inoculation is to introduce desired
AM fungal propagules into the rhizosphere of the
target plant (Jarstfer and Sylvia
1992
). Various
methods of AM fungal inoculation for trans-
planted and fi eld-sown crops have been detailed
by Bagyaraj (
1992
). The most common method
is to place the inoculum below the seed or seed-
ling, prior to seeding or planting. Seedlings raised
in sterilized or unsterilized nursery beds or con-
tainers containing selected AM fungi can be
transplanted after mycorrhizal association is well
established. This method has been successfully
used for agronomic crops like chilli, fi nger millet,
tomato and tobacco (
Nicotina tabacum
) (Govinda
Rao et al.
1983
; Sreeramulu and Bagyaraj
1986
).
For fi eld-sown crops, AM fungi can be applied as
seed coating (Hattings and Gerdemann
1975
),
mycorrhizal pellets (Hayman et al.
1981
; Hall
and Kelson
1981
), fl uid drilling (Hayman et al.
1981
) and inoculation in furrows (Hayman et al.
1981
; Powell and Bagyaraj
1982
).
References
Abd-Ellatif SA, Abdel Rahman RA, Mazen MBH,
El-Enany AE, Allam N (2012) Biotechnological
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Abdel-Aziz RA, Radwan SMA, Abdel-Kader MM,
Barakat MIA (1997) Biocontrol of faba bean root-rot
using VA mycorrhizae and its effect on biological
nitrogen fi xation. Egypt J Microbiol 31:273-286
Abdul-Khaliq, Gupta ML, Alam A (2001)
Biotechnological approaches for mass production of
arbuscular mycorrhizal fungi: current scenario and
future strategies. In: Mukerji KG, Manoharachary C,
Chamola BP (eds) Techniques in mycorrhizal stud-
ies. Kluwer Academic Publishers, The Netherlands,
pp 299-312
Abo-Rekab ZA, Darwesh RSS, Hassan N (2010) Effect of
arbuscular mycorrhizal fungi, NPK complete fertiliz-
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tized date palm plantlets. Mesopot J Agric 38:9-19
Affokpon A, Coyne DL, Lawouin L, Tossou C, Agbèdè
RD, Coosemans J (2011) Effectiveness of native West
African arbuscular mycorrhizal fungi in protecting
vegetable crops against root-knot nematodes. Biol
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Ahmed AM, Abdelhafez P, Abdelmonsief A (2009) Effect
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nutrient content of cantaloupe and cucumber under
7
Conclusion
The role of AM fungi in enhancing plant growth
is proved beyond doubt both under on-fi eld and
off-fi eld conditions. Responses to AM fungal
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