Nitrogen Cycle

Question 1

Nitrogen use efficiency _____%

Answer 1

<50%

Question 2

Internal N transformations

Answer 2

mineralization, immobilization, nitrification

Question 3

N loss paths

Answer 3

denitrification, volatilization, leaching

Question 4

types of N fixation

Answer 4

Lightning (3%), Biological (67%), Industrial (30%)

Question 5

biological N fixation

Answer 5

pulling N2 out of atmosphere turning it to NH3

Question 6

industrial N fixation

Answer 6

fertilizers made at high temp and pressure

Question 7

WHat % of soil N is organic matter

Answer 7

99%

Question 8

Mineralization

Answer 8

soil organisms break down organic matter to release simpler N, then transform it into an inorganic form

Question 9

Immobilization

Answer 9

microorganisms converting N from inorganic to organic

Question 10

Net effect of mineralization/immobilization depends on

Answer 10

carbon:nitrogen ratio (decomposition)

Question 11

Ideal Microbial diet (C:N)

Answer 11

24 carbon : 1 nitrogen

Question 12

Nitrification

Answer 12

ammonium being oxidized rapidly by bacteria into NO3- in well aerated soils

Question 13

Denitrification

Answer 13

multi step process that converts NO3- to N2 in oxygen deprived areas

Question 14

Volatilization

Answer 14

converts NH4+ in the soil to NH3 in the air

Question 15

why is No3- more prone to leaching

Answer 15

it is dissolvable in water unlike NH4+