5.1
What is famine? Where do most famines occur?
A What is famine?
1
a
Complete the chart below to show how famine occurs.
When the amount of food is ( enough /
not enough) to feed the population
Food ___shortages___ occur
Situation become severe and lasts for a long
period of time causing many people to die
__Famine___ occurs
b
What is famine?
It refers to the situation in which many people die because of severe food shortages.
B
2
Where does famine most likely to occur?
Figure 1 shows the risk of food shortages by country.
Figure 1
Risk of food shortages by country
1
a
Complete Table 1 to show the risk of food shortages in different countries.
Table 1
Countries
GNP per capita (2007)
Risk of food shortages
China
US$2,370
Moderate
Ethiopia
US$220
High
Japan
US$37,790
Low
Mexico
US$9,400
Moderate
Niger
US$280
High
USA
US$46,040
Low
Source: The World Bank
Note: According to the World Bank, countries with GNP per capita of US$11,456 or above are considered
as more developed countries, countries with GNP per capita of US$11,455 or below are considered as less
developed countries.
b
Refer to Table 1.
i
What is the level of economic development of the countries with low risk of food
shortages?
Countries with low risk of food shortages are mostly ( more / less ) developed
countries. They have a ( high / low ) GNP per capita and therefore a ( high / low )
level of economic development.
ii
What is the level of economic development of the countries with high risk of food
shortages?
Countries with high risk of food shortages are mostly
less developed countries.
They have a low GNP per capita and therefore a low level of economic
development.
iii
What do you notice about the relationship between the level of economic
development and the risk of food shortages?
Countries with a low level of economic development have a high risk of food
shortages.
2
C
Why do some countries have a high risk of food shortages whereas
others have a low risk?
3
Table 2 shows the production and consumption of cereals in the world, USA, Niger and Japan.
Study Figure 1 (p. 1), Tables 1 (p.2) and 2 and answer the following questions.
Table 2
World
USA
Niger
Japan
Production of cereals
(million tonnes)
2,054.7 (2005–6)
335 (2003)
3.3 (2002)
12.4 (2005)
Consumption of cereals
(million tonnes)
2,042.2 (2005–6)
32 (2003)
3.6 (2002)
22 (2005)
Source: UNFAO
a
Based on the world figures in Table 2, is there enough food to feed the world population?
Yes, the world production of cereals is larger than consumption. This means that the
world have enough food to feed the population.
b
i
Which country has cereal production greater than cereal consumption?
The USA.
ii
Which countries have cereal consumption greater than cereal production?
Niger and Japan.
iii
Which country has food shortages?
Niger.
c
Based on the world figures, we can see that the world produce enough cereals for
everyone to consume. So why do food shortages still exist?
The basic reason for causing food shortages in some countries is the world supply of food
is ( even / uneven ). Some countries, such as the USA, produce ( more / less ) food than
their people demand. These countries have surplus food. They can _____export______
and sell their surplus food in the world market. However, some countries, such as Niger,
produce ( more / less ) food than their people demand. Moreover, they are too poor to
import food to meet their demand, therefore, food shortages occur in these countries.
3
d
Japan also has cereal consumption greater than cereal production. Why doesn’t it have
food shortages?
This is because it has money to import food to solve the problem of food shortages.
e
What can you conclude about the reasons causing food shortages and famine in some
countries but not others? Fill in the following boxes by referring to the hints below.
i
What affect food demand of a country?
ii&iii What affect food supply of a country?
iv
i
What is the relation between food demand and food supply that will lead to
famine ( <, > or = )?
_Population
iv ＞ Food supply
Food demand
ii
___Local food
production___
size_______
____________
Food shortages
iii
Prolonged severe
conditions
Food imports_
____________
Famine
D
4
What are the characteristics found among countries where famine
occurs?
Table 3 shows the country profiles of Finland and Chad.
Table 3
Finland
Chad
1
Population (millions) (2007)
5.3
10.8
1
Annual population growth (%) (2007)
0.4
2.8
2
Birth rate (per 1,000 people) (2000–5)
11
47.6
1
Illiteracy rate (all adults) (%) (2007)
0
68.2
1
Life expectancy (years) (2007)
79
51
1
GNP per capita (US$) (2007)
44,300
540
4.6
71.4
3,190 (high)
1,980 (low)
Stable
Unstable, refugees and
conflict
3
Agricultural labour force (%) (2004)
Dietary energy consumption
(kcal/person/day) (2003–5)
3
Political stability
Source: 1 The World Bank
2
UN
3
UNFAO
4
a
Refer to Figure 1 on p. 1, what is the risk of food shortages in Finland and Chad
respectively?
Finland has a low risk of food shortages while Chad has a high risk of food
shortages.
b
Refer to Table 3. What are the characteristics of the country suffering from high risk of
food shortages?
i
ii
iii
Population characteristics
•
( Large / small ) population
•
( High / Low ) birth rate and a ( high / low ) population growth
•
( High / Low ) level of education
•
( Long / Short ) life expectancy
•
( High / Low ) dietary energy consumption
Economic development
•
( High / Low ) income
•
Rely heavily on ____agriculture____ for income
•
( High / Low ) level of economic development
Political stability
•
( Stable / Unstable ) political condition, with _____refugees____ and
____conflict_____
5
5.2
What are the factors affecting agricultural
production?
A What is agriculture? How can we classify agriculture into different
types?
1
What is agriculture?
Agriculture refers to the __________growing of crops___________ or rearing of livestock for
___food____ and ________raw materials_________.
2
How can we classify agriculture into different types? Complete Table 1 to show the way of
classifying agriculture.
Table 1
1
Inputs-land ratio/outputs-land ratio
______Intensive______ farming
•
Characteristics
•
Extensive farming
Farmland is small with much
•
Farmland is large with little labour.
labour.
•
The input and output per land area
The input and output per land area
is low.
is high.
Rice cultivation in South China or
Example
Shifting cultivation or other examples
other examples
6
Table 1 (continued)
2
Types of output
Livestock
____Arable____ farming
____Mixed____ farming
rearing/Pastoral farming
(Credit: Nigel
Dickinson/Still Pictures)
Farmers grow crops only.
Characteristics
Farmers raise animals
Farmers grow crops and
only.
raise animals on the same
farm.
Example
Cotton growing in the
Livestock rearing in
Wheat-sheep farming in
USA or other examples
South China or other
south-east Australia or
examples
other examples
3
Uses of outputs
_____Subsistence_____ farming
Characteristics Outputs are for self-consumption
Example
Nomadic herding or other examples
Commercial farming
Outputs are for sale
Cattle ranching in tropical rainforests
or other examples
4
Permanence of farmland or pasture used
____Sedentary_____ farming
Characteristics
Example
Non-sedentary farming
Farmers grow crops or rear livestock at
Farmers move from time to time in
a permanent land site.
search of suitable land or pasture.
Rice cultivation in Indonesia or other
examples
Shifting cultivation or other examples
7
Table 1 (continued)
5
Level of technology
_____Low-technology_____ farming
Farming activity uses low technology
High-technology farming
•
and little energy.
Farming activity is __specialized__,
highly mechanized and
____commercialized____.
Characteristics
•
Much energy from ______fossil
fuels_____ such as oil, is used to
run the farm.
Example
Rice cultivation in South China or
Irrigation farming in southern
other examples
California or other examples
B What is a farming system?
3
Complete the flow chart below to show an arable farming system.
Inputs
__Farming processes__
Physical
Plouging, sowing,
planting, irrigating,
harvesting, etc.
___Climate___, ____soil____,
Outputs
Useful
Useless
Crops
Waste
land, ___water___ and seeds
Cultural
Cash
Market
____Labour____, capital,
____technology_____, market,
Self-consumption
__transport__ and government
8
C What are the factors affecting agriculture?
4
Complete Figure 1 below to show the factors affecting agriculture.
Soil
Temperature
Rainfall
Climate
Land
Relief
Wind
Drainage
Physical factors
Interplay
Farming
characteristics
of an area
Cultural factors
Capital
Labour
Transport
Technologies
Market
Institutional factors
Figure 1
Physical factors
5
Figure 2 shows the frost-free periods of the world.
Figure 2
9
a
What can you notice about the relationship between annual mean temperature and the
length of the frost-free period?
The higher the annual mean temperature, the ____longer____ the length of the frost-free
period.
b
How does the length of the frost-free period affect the length of the growing season?
The length of the frost-free period determines the length of the growing season. This
means the longer the frost-free period, the _____longer the length of the growing
season___________________________.
c
If you were a farmer and you want to grow rice, which place will you choose to farm,
Place A or B? Why?
Place ( A / B ). It is because this place have a
higher annual mean temperature and
without frost-free period. Therefore, farming activity can be carried out throughout the
year.
d
Complete the flow chart below to show how temperature affect agriculture.
The length of the growing season
Temperature
Affects
The type of crop grown or livestock raised
6
Complete Table 2 to show how rainfall affects agriculture.
Table 2
Annual rainfall
•
Affects the _____types_____ of crops grown and the _____size_____ of production.
Types of crops grown
•
Areas with abundant rainfall are suitable
for growing _____water-demanding_____
Size of production
•
Areas with abundant rainfall can have a
( smaller / greater ) number of cropping.
crops such as wet rice.
•
Drier areas are suitable for growing
___dry___ crops such as wheat and barley.
10
Seasonal variations in rainfall
•
Variable and unreliable rainfall may ( increase / reduce ) crop yield
Intensity and duration of rainfall
•
Heavy showers may cause _____flooding_____ and drown the crops.
•
Prolonged ____drought_____ may cause crops to wither.
Unusual precipitation
•
Rainstorms, hailstorms, frost, etc. may ____damage_____ crops and bring huge economic
losses to farmers.
7
Below shows the effects of wind on agriculture. Fill in the box with ‘+’ or ‘－’ to indicate
whether it has positive or adverse effects on agriculture.
How does it affect agriculture
8
a
Onshore winds
+
Strong winds
－
Tropical cyclones
－
Bring moisture to coastal areas, thereby lengthen the
growing season.
Increase evaporation rate and therefore reduce soil
moisture and cause soil erosion.
Damage crops
Below shows the quality of soil. Which soil quality is favourable for crop growth? Tick
() the appropriate answers.
pH value
 Slightly acidic
 Strongly acidic or alkaline
Thickness of soil
 Thin
 Thick
Nutrient content/Soil fertility

 High
Moisture content
 Well-drained
 Poorly-drained
 Unstable and insufficient
 Stable and sufficient
Low
11
b
Figure 3 shows the physical environment of an area.
Figure 3
i
Which place is more favourable for farming? Why?
Place ( A / B / C ) is more favourable for farming. It is because the _______alluvial
soil on the flood plain is fertile and the soil is thick___________________________
__________. In addition, it is near a ____river_____ where irrigation water is
( insufficient / sufficient ). The river can also act as a means for transporting
____agricultural produce_________.
ii
(a) Explain why Place A is not suitable for farming.
The water table at Place A is ( high / low ), the soil may become
___waterlogged___. As most crops cannot grow well in waterlogged fields,
Place A is therefore not favourable for farming.
(b) What can be done to improve the soil condition of Place A in order to make it
more favourable for farming?
Man-made drainage systems with ditches and pipes can be installed to drain
away excess water from the soil.
c
Name ONE method which can help increase soil fertility.
Applying fertilizers/fallowing/crop rotation/cover cropping or any other
appropriate answers
12
9
Figure 4 shows the relief of an area in high-latitude regions in the Northern Hemisphere.
Figure 4
a
Relief, including altitude, aspect and gradient of the field, affects farming. Complete
Table 3 to show how these factors affect farming by referring to Figure 4.
Table 3
Place A
Place B
Place C
Altitude
Temperature ( increases / decreases ) and wind gets ( stronger / weaker ) with increasing altitude.
•
( Highland / Lowland )
•
( Highland / Lowland )
•
( Highland / Lowland )
•
Temperature: 30°C
•
Temperature: ___2___°C
•
Temperature:21°C
•
Located on ( south-facing /
•
Although located on
•
Located on ( south-facing /
Aspect
•
•
north-facing) slope.
( south-facing /
Receives ( more / less )
north-facing) slope, the air
sunshine  ( warmer /
temperature is low due to
sunshine ( warmer /
cooler )
high altitude
cooler )
_____Onshore winds_____
north-facing) slope.
•
•
Receives ( more / less )
Located in the ___rain____
provide moisture for crop
_____shadow_______, the
growth.
place is ( wet / dry ).
13
Place A
Place B
Place C
Gradient of the field
Gradient or slope of the field affects soil ____depth____ and ______mositure______ content.
•
Gradient: ( steep / gentle )
•
Gradient: ____steep____
•
Soil
•
Soil
- thickness: ( thin / thick )
- thickness: ____thin____
- moisture content: ( low /
- moisture content: ____low____
high )
because infiltration rate is ____low____ and surface run-off is
because infiltration rate is
_____fast_____, resulting in serious ________soil
( high / low ) and surface
erosion__________.
run-off is ( fast / slow ).
( More favourable /
( More favourable / Less favourable ) for farming
Less favourable ) for farming
b
i
What can be done to make farming possible in hilly areas?
Carrying out terracing.
ii
What are the advantages of the method you mentioned in Question bi?
Terracing can slow down surface run-off, increase infiltration and soil
moisture. It can prevent soil erosion.
Cultural factors
10
Table 4 shows some information about Countries A and B.
Table 4
Country A
Country B
Farm workers (number/hectare)
7.9
0.2
Yield per hectare (million tonnes/hectare)
22
18
Yield per worker (tonnes/hectare)
2.8
90
Compare the farming characteristics between Countries A and B.
•
Labour
Country ( A / B ) requires more labour in farming while Country ( A / B ) requires less
labour in farming.
14
•
Agricultural outputs
Yield per hectare in Country A is ( higher / lower ) than that in Country B, but yield per
worker is ( higher / lower ) than that in Country B.
11
Below shows some information about Farms A and B in different regions.
Farm A
•
Tractors utilization (number/1,000 hectare): 80
•
Number of farm workers (number/hectare): 0.09
•
Farm investment (US$/hectare): 2,800
Farm B
a
•
Tractors utilization ( number/1,000 hectare): 8
•
Number of farm workers (number/hectare): 4.8
•
Farm investment (US$/hectare): 820
Complete Table 5 to show the farming characteristics of Farms A and B.
Table 5
Farm A
Farm B
Labour input
Low
High
Amount of machines used in
farm production
Large
Small
Capital input
Large
Small
Capital-intensive
Labour-intensive
Farming method
b
Which farm is more likely to be located in a more developed country? Why?
Farm A. It is because its capital input is large and only farmers in more developed
country are capable to invest a lot of money in farming.
12
a
What are the benefits brought by the means of farming technologies shown on p. 16? Put
the letters in the second column of Table 6 on p. 16.
15
Means of farming technologies:
A
Irrigation and drainage
C
E
Mechanization
Biotechnology
Applying pesticides
G
Table 6
B
D
F
Using greenhouses
Applying fertilizers
Benefits brought by farming technologies
Benefits
b
Applying herbicides
Means
Stabilize water supply
A
Prevent weeds from competing for nutrients with crops
D
Increase farm efficiency and quality of farm work
B
Regulate temperature for plant growth
F
Improve the quality of crops and increase farm production
C
Protect crops from pest
E
Improve soil fertility
G
Do less developed countries commonly use advanced technologies in farming? Why?
No, less developed countries rarely use advanced technologies in farming. It is because
farmers are poor and lack of necessary knowledge to use advanced technologies.
13
a
What are the TWO kinds of markets for farm produce?
Local and overseas markets.
b
Explain how market forces affect commercial farming.
Market forces affect commercial farmers’ decisions on the ____types____ and quantity of
crops grown or animals reared. For example, when the ____demand ____ for and price of
a particular crop increase, farmers will grow ( more / less ).
16
14
Figure 5 shows two farm locations. Figure 6 shows some information about Farms A and B.
Farm A
Farm produce: cherries,
strawberries, and kiwi fruit
Markets: local and overseas
Farm B
Farm produce: wheat, cotton
and corn
Markets: local and overseas
Figure 5
a
Figure 6
Which location is Farm A more likely to locate? Why?
Farm A is more likely to locate at Location ( I / II ). This is because its farm produce are
more _____perishable______ than those of Farm B, being near the _______main
road____ can help transport the farm produce to the market within a ( long / short ) time.
b
Produce of Farms A and B are for export. If you were the owner of these two farms,
which means of transport will you use to transport these farm produce to overseas
markets respectively? Why?
I will transport the farm produce of Farm A by (sea / air ) and Farm B by ( sea / air ). This
is because the produce of Farm A are _____more perishable_____ than those of Farm B.
Produce of Farm A need to be delivered to the markets within a short time to prevent loss.
In addition, they are of ( higher / lower ) value which can afford the ( higher / lower )
transport cost.
15
How do institutional factors affect agriculture?
Institutional factors affect agriculture in the following two aspects:
•
______Land ownership______
Farmers who own the farmland are ( more / less ) willing to invest in their farm on a
long-term basis such as improving the quality of the soil.
17
•
Government policies
In ( less / more ) developed countries, governments have a strong influence on farming.
Government policies such as ___________providing technological aid___________ and
______subsidies______ will encourage farmers to adopt farming technologies and to
grow more.
D How do physical and cultural factors shape the characteristics of
farming in an area?
16
Refer to Figure 1 on p. 9. How do physical and cultural factors shape the farming
characteristics in an area?
The interaction of physical and cultural factors shapes the farming characteristics in an area.
18
5.3
What are the agricultural characteristics of
nomadic herding in the Sahel?
A Where is the Sahel?
1
Figure 1 shows the location of the Sahel. Figure 2 shows some information of the Sahel.
a
Mark the location of the Sahel in RED on Figure 1.
b
Complete Figure 2 about the information of the Sahel.
Figure 1
Information of the Sahel
•
It is a belt of land at the _____southern_____ edge of the Sahara Desert in Africa.
•
It lies approximately between __11°__N and __20°__N.
•
It is a strip of ___semi-arid___ land of over 6,000 km long and 450 km wide.
•
It separates the Sahara Desert to the north and the ___savanna____ to the south.
•
It is fairly uniform in ____climate____ and ____soil____.
•
People living in the Sahel have a similar _____lifestyle_____.
Figure 2
19
B
2
What is the physical environment of the Sahel?
Complete Table 1 to show the physical environment of the Sahel.
Table 1
1 Climate
Figure 3 A climatic graph
of Zinder
Figure 4
Temperature
•
Annual mean temperature
•
Annual rainfall is ___low/scanty___, between 200 mm and 600 mm.
is ____high____
•
Much of the rainwater is lost through ___evapotranspiration__ as the
throughout the year.
•
temperature is ____high____ throughout the year.
Annual range of
•
Rainfall concentrates in ( winter / summer ) months.
temperature is
•
Rainfall is ____variable____ and ____unreliable____. It may be wet in
____small____.
•
Annual rainfall in the Sahel
Rainfall
one year and then very dry in other years.
Complete the flow chart below to show why the Sahel has such temperature and rainfall characteristics.
The Sahel has hot and dry ( onshore /
___Onshore___ winds from the south cannot
offshore ) winds in both summer and
penetrate inland and lose most of the
winter
____moisture____ when they reach the Sahel
___Hot___ and ___dry___ throughout the year. It
has a ______tropical semi-arid________ climate.
20
Table 1 (continued)
2 Drainage and relief
Figure 5
Drainage and relief of the Sahel
Drainage
•
Relief
•
Two major rivers—the River ____Niger____
Much of the Sahel has a ___low___ relief,
and the River ____Nile____ draining a relative
highlands are only found on the ( western /
( large / small ) area in the Sahel.
eastern ) part.
3 Soils and vegetation
•
Complete the flow chart below to show the characteristics of soils and vegetation in the Sahel.
___Thin___ and
___High___ evaporation rate caused by strong solar
____infertile____ brown soils
radiation ( increases / reduces ) soil moisture
( Hinders / Favours ) plant growth
• Only ____drought____-resistant plants can adapt to the environment.
• Vegetation are ( densely / sparsely ) distributed.
• The major types of vegetation are ____grassland____ and ____shrubs____.
•
How can grassland and shrubs help protect the soil?
The roots of shrubs and grasses can hold the soil, therefore preventing the topsoil from being
blown away by strong winds.
21
C
3
How do people in the Sahel make a living?
Figure 6 shows the type of farming commonly practised in the Sahel.
Figure 6
a
Name the type of farming.
Nomadic herding.
b
Briefly describe how the type of farming you mentioned in Question a is practised in the
Sahel.
Nomads rear a ( small / large ) number of herds around _______water source_______.
When _____pasture_____ is exhausted, they then move to another site to look for
____water_____ and ____pasture____. The old site is left _____fallow_____. When the
water and pasture of the new site are exhausted, nomads move their herds again to
another site and the cycle continues.
22
D
4
What is the nomadic herding system in the Sahel? What are the
farming constraints in the Sahel?
a
Complete the flow chart below to show the nomadic herding system in the Sahel.
Inputs
Physical
1
Farming processes
Grazing, watering, milking,
Climate: ___Strong___ solar
mating, processing dairy
radiation, ___low___ and
products, etc.
unreliable rainfall
2
_____Infertile brown_____ soils
3
Shrubs and ____grassland_____
4
_____Herds_____
Cultural
1
Labour
2
___Simple____ and traditional
Outputs
Milk, meat and hides
•
use
technology
3
b
Mainly for ___subsistence___
•
___Little___ energy input
A small part for ___sale___
What kind of farming does nomadic herding belong? Tick () the appropriate answers.
 Extensive farming

Mixed farming


Low-technology farming
 Commercial farming

High-technology farming
 Subsistence farming

Sedentary farming
 Arable farming
 Non-sedentary farming
Intensive farming
 Pastoral farming
c
i
Which of the following are farming constraints in the Sahel? Tick () the
appropriate answers.
ii
For each of the farming constraints in the Sahel, write down ‘P’ on the line if it is a
physical constraint and ‘C’ if it is a cultural constraint.

Infertile soil
P

Waterlogged soil
 Shortage of labour
 Poverty
 Drought
P

Low level of technology
 Thin soil
P

Rugged relief
C
C
23
5
a
What is carrying capacity of the land?
Carrying capacity of the land refers to the maximum size of population that the
available resources of the land can support.
b
What is the carrying capacity of the land in the Sahel, high or low? Why?
The carrying capacity of the land in the Sahel is low. This is because it has a few
resources, it can only support a small population.
E
6
How do the nomads in the Sahel adapt to the environment?
a
Nomadic herding has been considered as an ecologically balanced system. Refer to
Figure 6 on p. 22, explain why it is an ecologically balanced system.
Nomads move their herds from one place to another for ____pastures____ and
____water____. When the pasture is exhausted in a place, ____________they migrate to
new pastures for grazing_________________________________. The old site will be
left _____fallow______ for soil to recover its _____nutrients_____ and
______water______, and thereby help the grass _____regenerate_____. By doing so, the
___________ecological balance___________ is maintained.
b
What do we call the farming practice if nomads move their herds on seasonal basis?
Transhumance.
7
Figure 7 shows the type and number of animals reared by a nomad household. Table 2 shows
the types of food required by the animals.
Table 2
Animals Food required
Camel
The branches and
leaves of trees and
shrubs
Goat
The leaves of trees
and shrubs
Cattle
Grass
Figure 7
24
What are the advantages for nomads to keep a variety of animal species?
Different animals graze on different types of plants. Keeping a variety of animals can
prevent the complete consumption of any one particular plant species. In addition, the
various animal species can provide nomads with a rich mix of dairy products at different
times.
8
Figure 8 shows the size of herds under different conditions.
a
When rainfall is inadequate or when there
is drought
b
When rainfall is adequate and vegetation
condition is favourable
Figure 8
a
What can you notice about the size of herds under different conditions?
•
When rainfall is inadequate or when there is drought, ____________the size of herd
is small____________________.
•
When rainfall is adequate and vegetation condition is favourable, ________the size
of herd is large__________________________.
b
What is the advantage of controlling the size of the herd under different conditions?
The thorny plants and rough grasses, which the herd live on, can grow well and the
ecological balance can be maintained.
F
9
What has caused environmental degradation in the Sahel?
Figure 9 shows variability in rainfall averages from June to October in the Sahel, 1950-2004.
Source: Adapted from JISAO (A
joint institute between the
University of Washington and
the NOAA)
Figure 9
25
a
Describe the rainfall pattern in the Sahel.
Rainfall varies greatly from year to year. It is variable and unreliable.
b
Between 1950 and 2004, how many years was rainfall below the long-term mean value?
Thirty years.
c
What natural hazard might occur under such a situation?
Drought.
d
Complete the flow chart below to show how nature has caused environmental
degradation in the Sahel.
Drought
Pasture available to
herds ( ↓ / ↑ )
Nomads move in search of
water and pasture
Prolonged ___drought___
Vegetation ( can / cannot ) regenerate.
Pasture and water are used up
Without ______vegetation cover______ and
with low soil moisture, soil ____erosion____
become serious
The land is degraded and gradually
become ____unproductive____
Environmental degradation
Desertification
26
10
Complete Table 3 to show how humans have caused environmental degradation in the Sahel.
Table 3
1 Increase in population
•
The Sahel has a ( slow / rapid ) increase in population due to ___high____ birth rates and
____low____ death rates.
•
Increase in population will lead to the following practices:
Converting grazing
land to farmland
Reducing __fallowing_
____periods____
Overgrazing
Depletion of
____soil nutrients____
Depletion of
____soil nutrients____
_____Pasture____ is
consumed faster than it
is able to regenerate
( Increases / Reduces ) pressure on the land
Population ( < / > ) carrying capacity of the land
____Land____ degradation
Desertification
2 Misuse of water resources
•
In order to get taxes from the nomads, the local governments in the Sahel has encouraged
the nomads to become _____sedentary_____ pastoralists.
•
Many local governments dig ____boreholes____ to tap water from underground to
____increase____ water supply for nomads. This encourages nomads to graze
___more___ animals.
•
_____Overgrazing_____ occurs and the land around boreholes is damaged.
•
Water table ____drops____ as much of the ground water is used up.
27
5.4
What are the agricultural characteristics of
irrigation farming in southern California?
A Where is southern California? What is the physical environment of
southern California?
1
Complete Table 1 to show the location and physical environment of southern California.
Location
Table 1
•
California is located in the ______south-western______ coast of the USA.
•
Southern California is a region extending roughly from ___32___°N to ___38___°N.
Relief and drainage
1 Relief
•
Much of the land is ____highland____
of over 400 metres, which includes the
_______Coast Ranges______ along the
coast and the ______Sierra
Physical environment
Nevada_______ to the east.
•
Most of the lowlands are found in the
_____Central Valley_____ and the
_____Imperial Valley____.
2 Drainage
•
Major rivers draining the Central Valley
are the _____Sacramento____ River and
Figure 1
The relief and drainage systems in
California
the ______San Joaquin_____ River.
•
Major river draining the Imperial Valley
is the _____Colorado_____ River
28
Table 1 (continued)
Physical environment
Climate
Figure 2
The climatic differences within California
1 Temperature
•
2
Temperature and evaporation rate _____increases____ towards the south.
Rainfall
•
Rainfall __decreases__ towards the south and towards the _____inland_____ areas.
•
Rainfall in southern California is ____seasonal____ and ____scanty____.
•
In most parts of southern California, winter is warm and ____wet____ while summer is hot
and ____dry___. It has a ______Mediterranean______ climate.
•
In the southern tip of California, rainfall is scarce because the area is affected by
____offshore____ winds for most of the year. It has a _____subtropical desert_____ climate.
•
Rainfall in the coastal area is ___high___ because it receives ___relief___ rain. Rainfall in
the inland areas is ___low___ because it is located in the _____rain shadow_____.
29
Table 1 (continued)
Soil and vegetation
Complete the flow chart below to show the characteristics of the soil and how it affects plant
growth.
___High___
___Salts___ beneath
evaporation rate
the soil are brought to
( Favours / Hinders )
plant growth
the surface
___Little___ vegetation cover
Most soils are ____alkaline____ and
____infertile____
___Little___ organic matter
B What are the characteristics of the irrigation farming system in
southern California?
Figure 3 shows an arable farming system in southern California.
Physical
1
Ploughing, seeding, planting,
• Temperature: 12°C–32°C
irrigation, pest control,
• Low annual rainfall: about 200–450 mm
fertilizing, harvesting
2
Alkaline and infertile soil
3
Extensive lowland in the Central Valley and the
4
5
Farming processes
Climate:
Outputs
Imperial Valley
Inputs
2
Water supply from the San Joaquin River and
Useful outputs: cash crops
the Colorado River
such as fruits, vegetables, etc.
Seeds of one or two crops
Cultural
1
Irrigation water from various water schemes
2
Research and technology
3
Chemicals, including pesticides and fertilizers
4
High capital investment
5
Hired and contract labour
6
Government aid/policies
7
Rail or road transport
Local and overseas markets
Cash
Figure 3
30
a
What are the major characteristics of the farming system shown in Figure 3? Tick () the
appropriate answers.
b
 Extensive


 Capital-intensive
Intensive
Labour-intensive
 Subsistence

 Commercialized and specialized
 High-technology
 Arable
 Sedentary
 Pastoral
 Non-sedentary
Low-technology
What can you conclude about the farming system in southern California?
•
Physical input: ( Favourable / Unfavourable )
•
Cultural input: (High / Low )
•
Farming processes: ( Simple / Specialized )
•
Output: ____Cash____ crop
C What are the farming constraints in southern California?
3
Complete Table 2 to show the farming constraints in southern California.
Table 2
How the farming
constraint affect farming
Farming constraints
Water
•
____Low____ and ____unreliable____ rainfall
•
Most rain falls in _____winter_____
enough_ water for crop
•
______Subtropical desert_______ climate in the
growth
Physical constraints
shortages
•
_Insufficient/Not
southern tip
•
Low rainfall in the Central Valley because of the
_____rain shadow____ effect
•
Alkaline
and
infertile
soil
•
High temperatures  __high__ evaporation
•
Alkaline soil is
rates  ____salinization____ of soil
( favourable /
High temperatures with low rainfall make it
unfavourable ) for
difficult for rocks to ___decompose___ into
growing crops
soils and release ___nutrients___
•
Low soil fertility
( increases / reduces )
crop yield
31
Table 2 (continued)
How the farming
constraint affect farming
Farming constraints
Physical constraints
Lack of
•
Relief is ___hilly___ as a whole
•
( Extensive / Limited ) lowlands are found in
good
•
Lack of ___arable___
land for farming
the area
quality
•
The quality of existing flat land is not good
farmland
•
The presence of ____deserts____ in the south
hinders the expansion of farm areas
Pests and
•
diseases
____Exotic____ pests and diseases affect crops
•
and animals in the area
__Destroys___ crops and
causes ___economic
Cultural
constraints
loss____ to farmers
Inadequate •
farm
•
Few young people are willing to work as
farmers.
Insufficient/Not enough
farm workers during
labour
peak season
D How can farmers overcome the farming constraints in southern
California?
4
Figure 4 shows large-scale irrigation schemes in California. Figure 5 briefly describes the
schemes.
Large-scale water schemes
•
Large ____dams____ and
____reservoirs____ are built to
store water
•
Water is transported to farms by
__aqueducts___ and __canals__
•
Provides irrigation water for a
( small / large ) area
•
Water is diverted from the north to
the south, and from the mountain
top of the Sierra Nevada
Figure 4
Figure 5
32
5
a
Refer to Figure 4 (p. 32), complete the descriptions in Figure 5 (p. 32).
b
List THREE advantages of developing large-scale irrigation schemes.
•
Provides reliable water source for farmland
•
Increases crop yield
•
Ensures a healthy growth of crops
•
Increases arable land
•
Improves the quality of farm produce
•
Extend growing season
•
More varieties of crops can be grown
(Any three)
Besides large-scale irrigation schemes, farmers also adopt different irrigation methods. Figure
6 shows the irrigation methods commonly adopted by farmers in southern California.
B
Gravity flow system
A Drip irrigation system
Irrigation water is drained into the
furrows and the water flows downslope
due to gravity.
Credit: Ed Young/Corbis
C Sprinkler system
Water drips to the root zone of a crop
from pinholes on small tubes above or
below the ground surface.
Water is spread evenly on the ground
surface by jetting water into the air.
Figure 6
a
Name the irrigation methods shown in Figure 6. Fill in the boxes A, B and C.
b
Complete Table 3 (p. 34) to show the advantages and disadvantages of the irrigation
methods shown in Figure 6.
33
Table 3
Advantages
•
•
Disadvantages
Enhances efficient use of __water_,
•
Requires a ___high___ investment
chemical fertilizers and
and careful maintenance and
____pesticides____
planning in order to suit the
Reduces water loss through
environment
____evaporation____ and avoids
Irrigation
method A
____salinization____ of soil
•
( Hinders / Improves ) plant growth,
crop yield and quality
•
Minimize the negative impact on
the environment caused by overuse
of ____chemicals_____
•
Irrigation
method B
•
Irrigation
method C
Requires a ____small____ amount
•
Irrigation water is lost easily due to
of capital to install the irrigation
_____high evaporation rates______
system
___________________
( Increases / Reduces ) the area of
•
farmland
Causes _____salinization______ of
soil if too much water is irrigated
•
Much water is wasted in regions
where evaporation rate is __high__
6
Refer to Figure 7.
Genes
Spider
Scorpion
transfer
Genes
transfer
Genetically-modified
(GM) tomatoes
Figure 7
a
What do we call the farming technology shown in Figure 7?
Biotechnology/Genetic engineering.
34
b
7
a
What are the advantages of GM crops? Tick () the appropriate answers.
 Higher resistance against pests

 Higher resistance against diseases
 Fast growing
 Slow growing
 Higher yield
Less suitable for their surroundings
How do farmers in southern California overcome the problem of infertile soil and pest
attack?
They apply fertilizers to tackle the problem of infertile soil and apply pesticides to get
rid of pests.
b
8
List THREE advantages of applying chemicals in farming.
•
Improves physical environment for growing crops
•
Reduces crop failure
•
•
Improves crop yield
(Any three)
•
Improves crop quality
Maintains a stable yield
How do famers in southern California overcome the problem of inadequate farm labour?
•
Hiring workers
-
•
Hire workers from ___Mexico____ to do the farm work.
Mechanization
-
Use ____machines____ to replace farm labour. This can also increase farm
____productivity____ and the ____efficiency____ of farm work.
E
Do areas with similar natural environments have similar agricultural
characteristics?
9
a
Complete Table 4 on p. 64 in your textbook.
b
Do the Sahel and southern California have similar natural environments?
Yes, they have similar natural environments such as infertile soil, low and unreliable
rainfall.
c
Do the natural environments of the two areas favourable for farming?
No, the natural environments of the two areas are unfavourable for farming.
d
Do the two areas have similar agricultural characteristics and outcome?
No, the two areas have different agricultural characteristics and outcome.
35
e
What has caused such differences?
The differences in agricultural characteristics and outcome lie in the difference between
the levels of ____cultural____ inputs. Irrigation farming in southern California has
___high___ cultural inputs. Farmers have ___capital___ and ____technologies____ to
modify the unfavourable natural environment to suit their farming activities and increase
farm outputs.
In contrast, cultural inputs in the Sahel are ___low___. Farmers do not have
_____________capital and technologies to modify the natural environment and result in
low farm outputs________________________________________________________.
F
Are cultural factors becoming increasingly dominant over physical
factors in influencing agriculture?
10
a
Complete Table 6 on p. 67 in your textbook.
b
What can you notice about the levels of cultural inputs in less developed and more
developed regions respectively?
Cultural inputs in less developed regions are low while in more developed regions are
high.
c
In which region do you think cultural factors are more dominant than physical factors in
influencing agriculture? Why?
In more developed regions, cultural factors are more dominant than physical factors in
influencing agriculture. This is because even the physical environment is less
favourable, cultural inputs, such as capital and technologies can be used to modify the
natural environment. By doing so, the importance of physical factors in influencing
agriculture is lowered.
36
5.5
To what extent can technology help increase
agricultural production and alleviate food
shortages?
A What are the factors affecting food supply?
1
Boxes a-f below shows the factors affecting food supply.
a Relief, soil
and
drainage
b Natural
hazards
c
Climate
d
Farming
technologies and
level of
productivity
e
Economic
development
f Wars and
conflicts
Local food production
Food imports
______a, b, c, d, e, f______
________b, e, f________
Food supply
Physical factors (a, b, c)
Cultural factors (d, e, f)
Figure 1
a
Which factors affect local food production and food imports? Write the letters in the
space provided in Figure 1. (Hint: some factors affect both local food production and
food imports.)
b
Highlight the box in BLUE if it is a physical factor and RED if it is a cultural factor.
Physical factors
2
Briefly explain how the physical factors listed below affect food supply.
•
Relief, soil and drainage: ___Rugged___ relief, _infertile/poor_ soil and lack of irrigation
water are not favourable for farming. These farming constraints __reduce__ food supply.
•
Climate: _Low/Inadequate_ rainfall hinders the growth of crops and ____reduces____
farm outputs.
•
Natural hazards: Natural hazards such as flooding and drought ___damage___ crops and
cause ______crop failure______. This ___reduces___ food supply.
37
Cultural factors
3
Complete Table 1 to show how the cultural factors affect food supply.
Table 1
How the factor affect food supply
•
Farmers in less developed regions do not have the ___technological_
Farming technologies
______know-how______ nor ____capital_____ to employ advanced
and level of
technologies.
productivity
•
They usually farm with _____traditional______ farming methods
and the productivity is ____low____.
•
Theoretically, uneven distribution of food among countries can be
solved by _____food imports_____.
Economic
•
development
However, countries with the greatest need for imported food are
mostly __poor_ countries. They are unable to pay for imported food.
•
____Poverty____ is the major reason for being not able to secure
adequate food.
•
Social factors
Places with distinct ______social classes______ may have an
unequal distribution of food among various classes.
•
People of ____low____ social class are less able to obtain food.
•
Fields are left ____abandoned____ during wars as farmers leave
their fields and go to a safe place.
•
___Crops___ are destroyed and ____irrigation____ systems and
____transport____ are paralysed during wars.
Wars and conflict
•
A large number of people are displaced from their homes as
____refugees____.
•
Food supply becomes more scarce and this __increases__ food price.
•
____Distribution____ of food aid to hungry people becomes
difficult.
•
Political factors
Government and _______bureaucratic inefficiency______ can add to
food shortages problems.
•
In countries where ___corruption___ and bribery are common, it is
impossible to ensure the food can go to the needy.
38
B How does farming function as an agro-ecosystem?
4
a
What is an agro-ecosystem?
An agro-ecosystem is a human manipulated, agricultural system comprising of biotic
and abiotic components which are linked by energy flow and nutrient flow.
b
Complete Table 2 to show the characteristics of an agro-ecosystem in comparison with a
natural ecosystem.
Table 2
Biomass
( Small / Large ); mostly ___plants___
Biodiversity
( High / Low ); often __monoculture__
Food web
( Complex / Simple ); few trophic levels
Gene pool
( High / Low )
Productivity
( High / Low )
Nutrient
cycling
•
Interrupted by export of harvested crops as nutrient is lost from the
ecosystem
•
Largely maintained by external supplies, e.g. fertilizers
Energy
source
c
Sun and energy subsidies
Compare with the natural ecosystem, the food web and energy flow in an agro-ecosystem
is simple and short. Why?
In an agro-ecosystem, usually one or two crops are grown. In addition, pesticides and
herbicides are used to kill unwanted pests and weeds. This reduces biodiversity and
therefore simplifies the food web and shortens the energy flow.
d
How do farmers subsidize energy inputs in an agro-ecosystem?
They subsidize energy inputs by using labour, machines, fertilizers and pesticides.
C What price do we have to pay for using technologies?
5
Figure 2 on p. 40 shows how the misuse and overuse of pesticides threatens the natural
39
ecosystem.
a
Complete Figure 2.
Vicious cycle
Use of pesticides
Kill __target__ pests
Certain insects are
and other insects
killed completely
But
Increases the
Some pest species may
Other insect species
become ____resistant____
may suddenly rise in
number
to pesticides
____Breakdown____ of food chain
Loss of biodiversity
Figure 2
b
Rewrite the information shown in Figure 2 in paragraph form.
Pesticides may kill the target pests as well as other insects. When certain insects are
killed completely, other insect species may suddenly rise in numbers. This will lead to
a loss of biodiversity and a breakdown of food chain, threatening the natural
ecosystem.
On the other hand, some pest species may become resistant to pesticides. Farmers
will have to apply more pesticides to kill the target pests and this causes a vicious
cycle.
c
Besides threatening the natural ecosystem, misuse and overuse of pesticides also pollutes
the environment and affects human health. Explain.
Residual pesticides will reach the ground water and seriously pollute drinking water
supplies. Residual traces of pesticides on crops can contaminate food products. All
these will cause health problems to humans.
40
6
Complete Figure 3 to show how farming upset the natural ecosystem.
Clearance of ___natural
Loss of ___habitat___
vegetation______ for
for wildlife
Animals die
farming
Modifies the
Upsets the _____natural ecosystem______
____food web____
Figure 3
7
Figure 4 shows the negative impact caused by the excess use of fertilizers on aquatic
ecosystem.
Figure 4
a
Name the phenomenon shown in Figure 4.
Eutrophication.
b
Refer to Figure 4, briefly describe how the excess use of fertilizers causes the
phenomenon you mentioned in Question a.
When too many fertilizers are used, the excess fertilizers are washed into rivers.
Fertilizers provide nutrients for water plants and algae in the river. This causes rapid
growth of algae and water plants. The rapid growth of algae and water plants will use
up oxygen in the water. Fish and other aquatic life will die because of lack of oxygen.
41
8
Complete Figure 5 to show how the use of powerful machines causes soil erosion.
Use of powerful machines to carry out deep ploughing
____Loosens____ topsoil
____Compacts____ topsoil
Accelerates
•
___Wind___ and ___water___
•
Infiltration ( ↑ / ↓ )
Surface run-off ( ↑ / ↓ )
erosion
Accelerates
Water erosion
____Soil____ erosion is speeded up
Loss of ___topsoil___
• Soil fertility ( ↑ / ↓ )
• Land productivity ( ↑ / ↓ )
Figure 5
9
Figure 6 shows the soil problem found in southern California.
Figure 6
42
a
Name the soil problem shown in Figure 6 (p. 42).
Salinization.
b
Where does the soil problem mentioned in Question a commonly found?
It is commonly found in hot and dry areas where evaporation exceeds precipitation.
c
How does the soil problem mentioned in Question a occur?
In areas where evaporation is intense, salts in the soil are drawn upwards in solution
through capillary action. When water evaporates, salt is left on the soil surface.
Gradually, salts accumulate to form a crust of salt.
d
Describe how the soil problem mentioned in Question a can be worsened by excess use
of water for irrigation.
When excess water are applied to the soil, more salts are dissolved and brought to the
land surface, this worsens salinization.
e
How does the soil problem mentioned in Question a affect farming?
Excess salts hinder the growth of crops and lowers crop yield. Land affected by
salinization may become completely unproductive.
10
GM crops are crop plants created for human and animal consumption using biotechnology.
a
Some people said that GM crops may help to combat world hunger. Why did they say so?
It is because GM crops are resistant to ___insects___, viruses, diseases and drought, and
tolerant to ___herbicides___. In addition, they give ___higher___ yields and can be
grown in ___less___ favourable physical environment. All these help ___increase___
food production and therefore may help combat world hunger.
b
Despite the benefits brought by GM crops, some people protest against GM crops. What
are their arguments? Tick () the appropriate answers.

It have unknown effect on human health.

It may cause negative effect on the ecosystem.

It may contaminate non-GM crops

It may reduce biodiversity.

It may affect local food production in less developed countries as farmers have to
depend on more developed countries for GM seeds.
43
D How can we sustain a balance between the use of technology and
the environment?
11
Figure 7 shows the descriptions of three kinds of sustainable farming methods.
Farmers plant two or more crops
A
Multiple
cropping
consecutively or at the same time
on the same plot of land in a year.
Farmers use natural methods of pest
B
Organic
farming
control and apply manure to enrich the soil.
They do not use chemicals in farming.
Farmers make use of computers and other
C
Precision
agriculture
information technologies to apply inputs
such as water, fertilizers, etc. precisely.
Figure 7
a
Name farming methods A, B and C in the space provided in Figure 7.
b
Complete Table 3 below to show the advantages of the three farming methods.
Table 3
Advantages
•
Enriches ____biodiversity____ of the farm
•
____Increases____ total crop yields as different crops can be grown in different
Farming
method A
Farming
seasons
•
____Reduces____ soil erosion
•
Maintains soil ____fertility____
•
Conserves water and ____soil____
•
Causes less harm to the environment as farmers do not use ___chemicals___ in
farming
method B
•
Conserves ____water____ and soil
Farming
•
Improves the _____efficiency_____ of water, fertilizers and pesticides
method C
•
Helps ____raise____ profits and ____reduces____ environmental damage
•
Conserves ____water____ and ____soil____
44
12
Soil and water conservation is important in sustainable agriculture because they reduce soil
erosion and depletion, and therefore prevent land degradation.
a
Which of the following farming methods conserve soil and water? Tick () the
appropriate answers.
Mixed farming

Planting wind shelters
b
Crop rotation



Cover cropping
Crop residues on the field


Fallowing

Contour ploughing
Briefly explain how the following farming methods conserve soil.
•
Crop rotation
Different crops take up different nutrients. By growing different types of crops
in the same field in sequential seasons, depletion of certain nutrients can be avoided
and soils are given time to replenish.
•
Fallowing
Fallowing allows the fields to replenish its soil nutrients after years of cropping.
c
Besides the farming methods mentioned above. Name ONE method that can conserve
water in farming.
•
Irrigate at night
•
Grow water-efficient crops
•
Use treated urban waste water to irrigate the field
(Any one)
E
What can be done to alleviate food shortages apart from applying
farming technologies?
13
From the example of southern California, we learned that modern farming technology has
successfully increased farm productivity. However, the same tactics may not be applicable to
famine-prone countries to solve the problem of food shortages. Why?
As most of the famine-prone countries are ___less___ developed countries, they are
___poor____ and lack of __money/capital___ to apply modern farming technology. In
addition, farmers are of ____low____ education level and do not have the ____technological
know-how______________________ to employ modern farming technology. Therefore, the
45
problem of food shortages cannot be solved solely by applying modern farming technology.
In fact, there are numerous causes of food shortages in less developed countries. Among
them, ____poverty____ is the root cause.
14
The basis of solving the food shortage problem is to reduce rural poverty. How can this be
done?
The basis of solving food shortage problem is to reduce rural poverty. This can be done by
carrying out rural development. Rural development involves two aspects: development of
non-agricultural sectors and infrastructure.
•
To develop non-agricultural sectors, we can
-
set up small-scale industries such as setting up fruit processing factories in fruit
producing areas and diversifying agricultural activities to increase income
-
•
put more inputs such as fertilizers in farming to increase production
To enhance non-agricultural development, it is necessary to develop infrastructure. This
can be done through:
-
maintaining a reliable rural electricity supply in rural areas
-
improving rural-urban linkages to help transport farm produce to urban markets
-
setting up a healthy marketing mechanism for farm produce to stabilize farmer’s
income and for others to obtain food at a reasonable price
-
setting up a sound financial support system to let farmers and others have easy
access to loans and credit
46