Lecture 5 - Soils and Civilisations

Question 1

What is soil made of?

Answer 1

lots of things: air, living organisms, minerals, water and dead material

Question 2

Where is soil found?

Answer 2

on the terrestrial surface of the Earth

Question 3

What distinguishes between soil and unconsolidated rock?

Answer 3

The presence of life distinguishes soil and unconsolidated rocks

Question 4

What is soil a medium for?

Answer 4

Plant growth

Question 5

What does soil store and regulate?

Answer 5

Water and carbon

Question 6

A handful of soil has more biodiversity than the Amazon rainforest - true or false?

Answer 6

True

Question 7

Soil stores less carbon than all the forests and atmosphere on the planet - true or false?

Answer 7

False

Question 8

How is soil important for cultural heritage?

Answer 8

Stores fossils or preserved human creations preserved in the soil - e.g. Roman shields

Question 9

How is soil important for our urban areas and buildings?

Answer 9

Supports the structures

Question 10

What questions do we need to answer to determine how fast soil forms?

Answer 10

How deep is the soil (tape measure)

How long it has been forming for

Question 11

How do we determine soil forming rate?

Answer 11

depth/time to calculate a yearly growth rate (although we typically use longer time frames, e.g. mm per 1000 years because the rate is so slow

Question 12

What is the formation speed of soil like?

Answer 12

Incredibly slow

Question 13

What type of resource can we treat soil as because of it’s incredibly slow formation rate?

Answer 13

A non-renewable resource

Question 14

When do we believe agriculture began evolving?

Answer 14

around 8000-10,000 years ago

Question 15

How do we know agriculture was undertaken in the past?

Answer 15

Ancient farm tools and Egyptian tomb paintings

Question 16

What does a plough allow us to do?

Answer 16

to till large areas in a short period of time, as opposed to having to plant each crop individually

Question 17

What was the effect of farming in Greece in the past?

Answer 17

The destruction of trees, and planting of crops unconsolidated the land, resulting in a massively increased rate of erosion, in an area that had seen very little erosion before

Question 18

What are periods of soil instability in the past associated with?

Answer 18

the expansion of agriculture

Widespread grazing of cattle

Question 19

What are periods of soil stability associated with?

Answer 19

where people have invested in soil conservation

Question 20

What is the general trend with periods of soil instability overtime?

Answer 20

the soil erosion events are episodic, but have been more concentrated in more recent times

Question 21

What is the cycle of soil overuse?

Answer 21

Population growth leads to increasing food production and land use - destabilizes soil
Soil erosion increases, soil fertility decreases and crops fail
Land is abandoned and forests replanted
Allows for a period of stabilization and stability

Question 22

How many people has soil sustained over 50 million years?

Answer 22

Over 100 billion people

Question 23

How many people currently live with chronic undernourishment?

Answer 23

About 1 billion

Question 24

How many extra people is it estimated we will need to feed by 2050?

Answer 24

2.3 billion

Question 25

How much do we need to increase cereal production by to lift people out of poverty and support the extra people by 2050?

Answer 25

70%

Question 26

To increase cereal production by 70% what needs to change

Answer 26

Output in developing countries needs to double

Question 27

What environment do agricultural environments have the same erosion rate as?

Answer 27

Alpine regions

Question 28

Are agricultural lands at a soil surplus, or deficit

Answer 28

Deficit - more is being washed away than forming

Question 29

How we lose soil nutrients?

Answer 29

Harvesting (takes away nutrients) Gaseous emissions Soil leaching into the ground

Question 30

How much soil do we estimate is lost every year?

Answer 30

35 thousand million tonnes

Question 31

How much nitrogen is displaced yearly?

Answer 31

23-42 million tonnes

Question 32

How much phosphorous is displaced yearly?

Answer 32

13-26 million tonnes

Question 33

What happens if phosphorous and nitrogen flows into rivers/lakes?

Answer 33

Eutrophication

Question 34

Where is the biggest issues with soil nutrition?

Answer 34

Africa

Question 35

What is happening to soil nutrition in Africa?

Answer 35

soils are losing more nutrients than they’re gaining (by far)

Question 36

Which continent consumes the most fertilizer?

Answer 36

Asia

Question 37

How much fertilizer does Africa consume yearly?

Answer 37

Essentially 0

Question 38

How have production of rice field in Libya v China differed since the 1960s?

Answer 38

The rice yields in Liberia have remained essentially static, while in China they have been steadily rising since the 1960s

Question 39

Soil degradation is a factor in the fall of civilizations - true or false?

Answer 39

True

Question 40

Is soil erosion outpacing soil formation?

Answer 40

Yes

Question 41

What is happening to soil fertility in sub-Saharan Africa?

Answer 41

Falling dramatically

Question 42

What condition are soil resources throughout the world and whats happening to them?

Answer 42

only fair, poor or very poor condition and that conditions are getting worse in far more cases than they are improving

Question 43

Who reported on the global status of soils?

Answer 43

Intergovernmental Technical Panel on Soils

Question 44

What % of the Planet's ice-free surface has been cleared for crops or livestock?

Answer 44

35%

Question 45

What crop production reduction would there be by 2050 is action is not taken?

Answer 45

10%

Question 46

Is soil acidity a problem?

Answer 46

Yes, a huge one

Question 47

What 4 steps can we take to solve soil issues?

Answer 47

Minimize further degradation and restore in most effected areas Stabilize global stores of soil organic matter Reduce/stabilize global use of nitrogen and phosphorus fertilizer - increase use in regions of nutrient deficiency Improve our knowledge about the state and trend of soil conditions