Nitrogen cycle

Page
1

Slide 1

Nitrogen

in

the air

animal protein

dead plants & animals

urine & faeces

ammonia

nitrites

nitrates

plant made

protein

decomposition by bacteria & fungi

bacteria

(nitrifying bacteria)

nitrates absorbed

denitrifying

bacteria

root nodules

(containing nitrogen

fixing bacteria)

nitrogen fixing plant

eg pea, clover

bacteria

Slide 2

The nitrogen fixing bacteria

are found inlumps on the roots called root nodules. The bacteria and the plant have a symbiotic relationship: the bacteria benefits by having food and shelter from the plant and the plant benefits by having nitrates produced by the bacteria.

Roots of a legume plant (peas, beans and clover).