The bacteria, which reduce nitrates in the soil to gaseous nitrogen, are known as denitrifying bacteria such as:

Related Mcqs:

1. Relationship between nitrogen fixing bacteria and a legume plant is described as:

   A. Mutualistic
   B. Parasitic
   C. Saprophytic
   D. Commensal

2. Removal of top soil by soil erosion result in the loss of soil:

   A. Nitrites
   B. Nitrates
   C. Nitrogen
   D. Nitric and nitrous acids

3. The association of nodule bacteria with leguminous roots is known as:

   A. Saprophytism
   B. Symbiosis
   C. Epiphytism
   D. Parasitism

4. In water logged soil plants cannot grow properly because the soil is:

   A. Physiologically wet
   B. Physiologically dry
   C. Physically dry
   D. None of the above

5. When a plant first begins to wilts permanently in a pot, its 54.5 gms of soil has 4.5 gms of water. The PWP of this soil is:

   A. 4.50%
   B. 9%
   C. 8.25%
   D. 16.50%

6. The ration of volume of pores in the soil to the total soil volume is referred to as:

   A. Pore frequency ratio
   B. Pore density ration
   C. Pore abundance ratio
   D. Pore space ratio

7. When a soil has been thoroughly wetted and then allowed to drain until capillary movement of the water has stopped, the water content of the soil will give an estimate of it’s:

   A. Gravitational water
   B. Capillary water
   C. Field capacity
   D. Storage capacity

8. The natural nitrogen cycle is greatly affected by the excessive use of:

   A. Sulphate fertilizers
   B. Insecticides
   C. Phosphate fertilizers
   D. Nitrate fertilizers

9. The earth’s atmosphere contains over _____ % by volume of nitrogen gas:

   A. 58
   B. 68
   C. 78
   D. None of these

10. Nitrification takes place only in well aerated soils because the bacteria responsible for it are:

    A. Aerobic
    B. Anaerobic
    C. Parasites
    D. None of these