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...