Chapter 5

Question 1

is an essential primary macronutrient that commonly limits plant growth. In plants, N is a component of proteins and nucleic acids.

Answer 1

Nitrogen

Question 2

Atmosphere contains __% N2, __% O2, and ___% CO2 gas

Answer 2

Atmosphere contains 78% N2, 21% O2, and 0.04% CO2
gas

Question 3

Form of nitrogen in the atmosphere, this form of
nitrogen must be transformed to usable forms
before it is available for plant uptake

Answer 3

N2 (Nitrogen gas)

Question 4

Soil particles attract and retain ammonium on
cation exchange complexes. This form may be
directly taken up by plants

Answer 4

NH4+ (Ammonium)

Question 5

Must be converted to ammonium before it is used by plants. This conversion occurs with time and is
know as ______________.

Answer 5

Organic nitrogen - mineralization

Question 6

• Conversion of organic nitrogen to inorganic (NH4-N)
by microbes

Answer 6

Mineralization

Question 7

• is the decomposition of
  proteins and the release of amines or amine groups

Answer 7

Aminization

Question 8

• Amines, urea and
  amino acids produced during aminization of organic
  N are decomposed by other heterotrophs with
  release of NH4+

Answer 8

Ammonification

Question 9

Conversion of inorganic N (NO3
-& NH4+) into organic
forms

Answer 9

Immobilization

Question 10

Oxidation of ammonium to nitrate
• Carried out by autotrophs

Answer 10

Nitrification

Question 11

Biological reduction of nitrate (NO3-) and nitrite (NO2-)
to dinitrogen (N2) gas and nitrous oxide (N20). The process is mostly carried out by facultative
anaerobic
bacteria
(heterotrophs)

Answer 11

Denitrification

Question 12

These are natural fertilizers in which is bound to
organic
molecule such as animal manure,
decaying plant residues, industrial wastes and
many others.

Answer 12

Organic sources

Question 13

Synthetic ammonia process- occurs at 400-5000C
and 200-1,000 atmospheres

Answer 13

Chemical sources

Question 14

• requires about 1,1000C and
  highly purified N gas is reacted with calcium carbide
  to form calcium cyanamide

Answer 14

Cyanamide process

Question 15

which occurs in the earth’s atmosphere

Answer 15

Direct oxidation of N