Question

what is nitrogen fixation? mention two differences between nitrification and denitrification processes . name the organisms involved in these processes

Answer 1

the chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle.


Nitrification

Follows ammonification process
Transformation of ammonium to nitrate
Oxidation reaction
Facilitated by two main types of chemoautrophic aerobic bacteria: Nitrosomonas and Nitrobacter
Two –step process: conversion of ammonium to nitrite, then conversion of nitrite to nitrate
Creates a nitrogen nutrient form available for absorption by plant roots
Reactant (ammonium) found in urea from animal wastes and fertilizers, composts and decomposing cover crops or crop residues
Nitrifiers more sensitive to environmental stresses
Inhibited by flooding, high salinity, high acidity, high alkalinity, excessive tilling and toxic compounds
Favoured by aerobic conditions, pH between 6.5 and 8.5, temperatures between 16 and 35 degrees C and high clay content
Denitrification

1) Follows nitrification process.
2) Transformation of nitrate to nitrogenous gases, mainly nitrogen and nitrous oxide.
3)Reduction reaction.
4)Facilitated by heterotrophic facultative bacteria
5)Sequence of steps: conversion of nitrate to nitrite, to nitric oxide, to nitrous oxide and finally to nitrogen
6)Decontaminates wastewater and aquatic systems by lowering nitrate levels
7)Reactant (nitrate) formed by nitrification, while carbon sources for denitrifiers are found in manure, cover crops and crop residues, or provided by methanol or acetic acid
8)Denitrifiers less sensitive to environmental stresses
9)Inhibited by reduced nitrification, lowered nitrate levels, deep placement of coated controlled-release fertilizer and soil drainage

Answer 2

Answer:

Explanation:

These are the

the chemical processes by which atmospheric nitrogen is assimilated into organic compounds, especially by certain microorganisms as part of the nitrogen cycle.

Nitrification

Follows ammonification process

Transformation of ammonium to nitrate

Oxidation reaction

Facilitated by two main types of chemoautrophic aerobic bacteria: Nitrosomonas and Nitrobacter

Two –step process: conversion of ammonium to nitrite, then conversion of nitrite to nitrate

Creates a nitrogen nutrient form available for absorption by plant roots

Reactant (ammonium) found in urea from animal wastes and fertilizers, composts and decomposing cover crops or crop residues

Nitrifiers more sensitive to environmental stresses

Inhibited by flooding, high salinity, high acidity, high alkalinity, excessive tilling and toxic compounds

Favoured by aerobic conditions, pH between 6.5 and 8.5, temperatures between 16 and 35 degrees C and high clay content

Denitrification

1) Follows nitrification process.

2) Transformation of nitrate to nitrogenous gases, mainly nitrogen and nitrous oxide.

3)Reduction reaction.

4)Facilitated by heterotrophic facultative bacteria

5)Sequence of steps: conversion of nitrate to nitrite, to nitric oxide, to nitrous oxide and finally to nitrogen

6)Decontaminates wastewater and aquatic systems by lowering nitrate levels

7)Reactant (nitrate) formed by nitrification, while carbon sources for denitrifiers are found in manure, cover crops and crop residues, or provided by methanol or acetic acid

8)Denitrifiers less sensitive to environmental stresses

9)Inhibited by reduced nitrification, lowered nitrate levels, deep placement of coated controlled-release fertilizer and soil drainage