SOIL SCIENCE
1. Net nitrogen immobilization in soil occurs if the C/N is
a. Less than 20:1
b. Greater than 20:1
c. Greater than 35:1
d. Less than 15:1
e. None of the above
C
2. Individually, which among the following soil organisms have the least biomass?
a. Actinomycetes
b. Fungi
c. Batecria
d. Protozoa
e. Earthworm
D.
3. Which among the following soil organisms are acid loving?
a. Fungi
b. Protozoa
c. Bacteria
d. Actinomycetes
e. A and b above
A
4. Ammonia volatilization from NH4
+
-bearing fertilizers is not favored by which of the following?
a. High pH
b. High temperature
c. High CEC
d. A and B above
e. B and C above
C
5. Soil microorganisms degrade organic residues primarily for
a. Phosphorous and ATP
b. Carbon and energy
c. Nitrogen and energy
d. Phosphorous and energy
e. Nitrogen and phosphorous
B
6. The root nodule bacteria belong to the genus
a. Clostridium
b. Azotobacter
c. Rhizobium
d. Agrobacterium
e. None of the above
C.
7. The anaerobic non-symbiotic ntrogen fixing bacteria belong to the genus
a. Derxia
b. Clostridium
c. Azotobacter
d. Bradyrhizobium
e. Nitrobacter
B
8. Algae are considered as
a. Autotrophs
b. Photoautotrophs
c. Chemoautotrophs
d. Both a and b above
e. None of the above
D
9. The source of energy for blue-green algae is
a. Sunlight
b. Metabolism of glucose
c. Organic matter decomposition
d. Oxidation of inorganic compounds
e. None of the above
A.
10. The predominant available form of N under flooded soil condition is
a. NO3-N
b. Organic N
c. NH4-N
d. NO2-N
e. NH2-N
C.
11. The available form of nitrogen which predominates under upland condition is
a. Ammonia
b. Nitrite
c. Nitrate
d. Microbial biomass N
e. Fixed N
C.
12. The conversion of NO3 to N2 is referred to as
a. Nitrogen fixation
b. Denitrification
c. Immobilization
d. Volatilization
e. None of the above
B.
13. The percentage of organic N in the soil is approximately
a. 96-98%
b. 80-85%
c. 68-75%
d. 50-60%
e. 60-70%
A.
14. Nitrogen is added to the soil system by which of the following processes?
a. Leaching
b. Nitrogen fixation
c. Ammonia volatilization
d. A and b above
e. B and C above
B
15. The conversion of organic N to inorganic or mineral N is termed as
a. Immobilization
b. Nitrification
c. Mineralization
d. Ammonification
e. None of the above
C