Microbiology of Soils
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Denitrification
may be distinguished as _____________.
a. dissimilative
b. assimilative
c. both (a) and (b)
d. blue
baby syndrome
The
conversion of molecular nitrogen into ammonia is known as _____________.
a. nitrification
b. denitrification
c. nitrogen fixation
d. ammonification
The
breakdown of cattle manure in biogas is accomplished by which of the following
type of bacteria?
a. Hydrolytic
b. Transitional
c. methanogenic
d. All of these
Which
of the following species of different genera of bacteria are not capable of
transforming nitrate to nitrogen?
a. Achromobacter
b. Agrobacterium
c. Alcaligenes
d. None of these
Which
of the following fungi on infecting crop roots can improve their uptake of
phosphorus and other nutrients?
a. Saccharomyces
cerevisiae
b. VA Mycorrhiza
c. Candida
torulopsis
d. Aspergillus
niger
Syntrophism
involves _____________.
a. exchange of nutrients between two species
b. exchange
of nutrients among species
c. no
exchange of nutrients between two species
d. no exchange
of nutrients among species
Assimilative
denitrification is done by _____________.
a. plants
b. fungi
c. prokaryotes
d. all of these
The
groups of bacteria which have the ability to fix nitrogen from air to soil are _____________.
a. symbiotic
b. nonsymbiotic
c. both (a) and (b)
d. none
of these
The
nitrogenase consists of _____________.
a. dinitrogenase
b. dinitrogenase
reductase
c. both (a) and (b)
d. none
of these
The
crops which are involved in nitrogen fixation are _____________.
a. alfalfa
and clover
b. soybean
c. bean
and lupine
d. all of these
Some
microorganisms have the ability to increase the nitrogen content of soils, are
called as _____________.
a. nitrogen fixation
b. denitrification
c. nitrification
d. all
of these
Nitrogen
fixation _____________.
a. changes
the free nitrogen (N2) to a form usable by plants
b. especially
changes nitrogen compounds, mostly amines such as NH2
c. both (a) and (b)
d. fix
the free nitrogen (N2) by which it should not be usable by plants
Denitrification
is _____________.
a. reduction
of nitrate (NO3-) to nitrogen gas
b. reduction
of nitrate to organic nitrogen compounds
c. both (a) and (b)
d. changing
of atmospheric nitrogen (N2) to nitrogen compounds
Degree
of compost maturity can be assesed by _____________.
a. infrared
technique
b. germination
test
c. both (a) and (b)
d. none
of the above
The
energy value of biogas is typically _____________.
a. 400-700 BTU/ft3
b. 1,000
BTU/ft3
c. 1500
BTU/ft3
d. more
than 5000 BTU/ft3
For
rapid decomposition by microbes, the substrate should have a C/N ratio of _____________.
a. 10-20
b. 20-30
c. 30-40
d. 60-80
Which
are the main source of biofertilisers?
a. Cyanobacteria
b. Bacillus
c. Streptococcus
d. None
of these
The
organisms responsible for the characteristic musty or earth odor of a freshly
plowed field is/are _____________.
a. Nocardia
b. Streptomyces
c. Micromonospora
d. all of these
The
microbial ecosystem of soil includes _____________.
a. biotic
components of soil
b. abiotic
components of soil
c. biotic and abiotic components of soil
d. none
of the above
Denitrification
is carried out _____________.
a. usually
by facultative anaerobes
b. predominantly
by Pseudomonas spp
c. predominantly
by Bacillus spp
d. all of the above
Which
of the following soil microorganism is involved in the reduction of sulfates to
H2S?
a. Thiobacillus
thiooxidans
b. Desulfotomaculum
c. Rhodospirillum
d. Rhodomicrobium
The
diagnostic enzyme for nitrogen-fixing organisms is _____________.
a. nitrogenase
b. nitrate
reductase
c. nitrate
oxidase
d. none
of these