(a) Explain the following terms:
(i) putrefaction
(ii) nitrogen fixation
(iii) nitrification
(iv) denitrification
(b) State three differences between nitrogen fixation and denitrification.
(c) Explain how nitrogen from urine gets to the roots of plants. W
Explanation
(a) Explanation:
(I) Putrefaction: A process by which agents of decay/saprophytic/putrefying bacteria/fungi; decompose/breakdown; dead organic remains/waste products of other organisms; into ammonium compounds/nitrates.
(ii) Nitrogen fixation: The process by which free atmospheric nitrogen; is converted to nitrate in the soil; by thunder storm/bacteria in root noddles of legumes/soil.
(iii) Nitrification: The conversion of ammonia/ammonium compounds; to nitrites; then to nitrates; by denitrifying bacteria.
(iv)Denitrification: This is the conversion of nitrates; in the soil to atmospheric nitrogen; by nitrifying bacteria/ fungi.
(b)Differences between Nitrogen fixation and Denitrification
| Nitrogen Fixation | Denitrification |
| free atmosphere nitrogen is added to the soil | Nitrates in the soil is converted into atmospheric nitrogen |
| Nitrogen fixing bacteria are involved, it involves symbolic and non symbolic organism/bacteria | Denitrifying bacteria are involved; it involves purely non-symbiotic organism /bacteria. |
| Modern soil temperature is required | High temperature is required |
(c) How Nitrogen from Urine gets to the roots of plants: –
- When a person passes urine in the soil
- Ammonium compound/urea present in urine; is converted into nitrite
- by nitrifying bacteria/nitroso monas
- The nitrites are oxidized to nitrates
- by other nitrifying bacteria /nitrobacter
- Roots of plants absorb the nitrates.