(a) Explain the following terms: (i) putrefaction (ii) nitrogen fixation (iii) nitrification (iv) denitrification (b)...
(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.
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.