Desertification

Question 1

Desertification threatens approximately ____% of the world’s population

Answer 1

20%

Question 2

Name 4 natural causes of desertification

Answer 2

-Soil Erosion
-Rainfall patterns (becoming less predictcable eg. drought)
-Reduced vegetation
-Any rainfall being in short, intense bursts (increases surface runoff + soil erosion)

Question 3

Name 4 human causes of desertification

Answer 3

-Overgrazing
-Over-cultivation
-Deforestation
-Population growth

Question 4

How does over-cultivation lead to desertification

Answer 4

All the nutrients being taken up by crops means that there are none left for future vegetation to grow. (Reduced vegetation = more desertification)

Question 5

How does deforestation lead to desertification

Answer 5

Removes shade for the soil from intense sunlight so it dries out quicker AND Less roots to bind soil together so increased soil erosion and decreased infiltration/interception

Question 6

How does population growth lead to desertification

Answer 6

Puts pressure on the land as people raise more animals and crops which can lead to over-cultivation

Question 7

Reducing the risk of desertification often involves water and soil management - what were the local farmers in Australia encouraged to do?

Answer 7

Ponding bank - area of land enclosed by low walls to store water

Contour traps - Embankments built along the contour of slopes to prevent soil from being washed down during heavy rainfall

Question 8

The Desert National Park in the Thar desert was created in _______ to protect around _______km^2 of desert and reduce desertification

Answer 8

The Desert National Park in the Thar desert was created in 1992 to protect around 3000km^2 of desert and reduce desertification

Question 9

What term describes this?
A farming methode that combines agriculture with forestry, which means some trees remain.

Answer 9

Agroforestry

Question 10

How does afforestation reduce desertification? (5)

Answer 10

The roots bind soil together reducing soil erosion

Canopy offers shade to prevent soil from drying out

When it rains there is more interception and infiltration which reduces surface run-off

Nutrients in the soil can be replaced

Trees increase animal + insect activity which improves soil quality

Question 11

A community project in the Thar desert achieved what to reduce desertification? (and where?)

Answer 11

They planted 1 million trees at Bikaner in Western Rajasthan to form a “green wall”

Question 12

How do contour stones reduce soil erosion?

Answer 12

They are literally a physical barrier that prevents the soil from being blown or washed away, and they ensure dead organic matter stay in one place and can decompose to add nutrient to the soil.