Lecture 1: Soil degradation

Question 1

How does soil degradation cause erosion

Answer 1

removes OM and clay so less nutrients and CO2 released

Question 2

How does intensive agriculture damage soil

Answer 2

tilling
fertiliser
pesticides

Question 3

What is tillage

Answer 3

turning soils to expose organic C
releases CO2

Question 4

How are inorganic fertilsers made (N and P)

Answer 4

Haber-Bosch process of N2 gas to NH3
inorganic phosphate rock mining

Question 5

Phosphate rock cycle

Answer 5

weathering of bedrock releases unavailable P
converted to inorganic via microbes mineralisation
human and animal waste returns P to soils

Question 6

Limitations of P mining

Answer 6

energy intensive
degrading
running out
lower grade
leaching

Question 7

rhizosphere

Answer 7

soil area in contact with roots

Question 8

Soil formation

Answer 8

biogenic (requires microbes)

Question 9

Soil contains

Answer 9

hyphae
clay
humus
fungi
OM
plant debris

Question 10

Challenges of soil degradation

Answer 10

intensive agriculture bad
recovery mechanisms reduced due to farming
crop yield plateau
population increase