Module 41 Lesson

5.10 Consequences of
Agricultural Practices

Objective and Essential Learning

Explain how agricultural practices have environmental and
social consequences.

▪Environmental effects of agricultural land use include pollution, land cover change, desertification,
soil salinization, and conservation efforts.

▪Agricultural practices- including slash and burn, terraces, irrigation, deforestation, draining wetlands,
shifting cultivation, and pastoral nomadism- alter the landscape.

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Agricultural Practices Alter the Landscape

Shifting Cultivation

▪Practiced in periphery and semi-periphery
countries - South America, Central and West
Africa and Southeast Asia.

▪Farmers cultivate the land until the soil
becomes infertile.

▫Fallow (uncultivated) period is supposed
to allow the land to recover

▫Soil degradation if land does not
have an adequate fallow period.

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Shifting cultivation

• Shifting cultivation occurs when a plot of ground becomes infertile and

farmers need land for new gardens.

• Trees are cut down and vegetation is often burned, leaving a layer of ash

that contributes to soil fertility.

• When the patch of land is abandoned or left fallow, the forest regrows,

but with secondary vegetation that is very different from the old-growth
forest that was destroyed.

How agricultural practices alter the landscape

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Shifting cultivation

How agricultural practices alter the landscape

Agricultural Practices Alter the Landscape

Slash & Burn Agriculture

▪Type of shifting cultivation that permanently
alters the landscape.

▫Method: Cutting and burning forests in
order to create fields for cultivation.

▫Ash from burning provides
nutrients and fertilizes crops.

▪Results in deforestation and soil erosion

▫Half of the world’s topsoil has been lost
in the past 150 years.

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Agricultural Practices Alter the Landscape

Terrace Farming

▪Typically practiced by subsistence farmers in
mountainous areas.

▪Steps are built into the sides of hills and
mountain sides in order to cultivate
water-intensive crops like rice.

▫During rainfall, the water floods through
the steps without pulling out the plants
or causing soil erosion.

▪Allows land to be cultivated that would
otherwise be non-arable.

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Paddy rice terraces
• Terracing alters the landscape in different ways than flatland rice

paddies.

• Both create productive rice paddies, but the mountain terraces alter

the landscape at a greater scale than flatland rice paddies.

How agricultural practices alter the landscape

Agricultural Practices Alter the Landscape

Irrigation

▪Used to supplement rainfall by bringing water from its natural sources to farm fields
through systems of canals, ditches, and other methods.

▫Reservoirs and aquifers

▪Impacts the cultural landscape and results in depletion of water resources.

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Irrigation

• Over the past century, the amount of land under irrigation has

expanded with the development of new technologies that facilitate the
capture and delivery of water, including dams.

How agricultural practices alter the landscape

Irrigated agriculture: Farming that relies on the controlled application of
water to cultivated fields.

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Irrigation

How agricultural practices alter the landscape

Water mining: The use of deep-well drilling
technology and powerful industrial pumping
systems to remove water in the ground.

Aquifer: Underground water deposited hundreds
of thousands of years ago.

Agricultural Practices Alter the Landscape

Pastoral Nomadism

▪Practiced in semi-arid and arid
climates, subsistence farming.

▪Herders move animals seasonally
to graze

▪Results in soil erosion &
desertification

▫Process by which formerly
fertile lands become infertile.

▫Typically as a result of
droughts and overgrazing

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Nomadic pastoralism

• Nomadic pastoralism is a subsistence agricultural system and a social

system in which groups of families travel together with their herds.

• Many pastoralists have been forced off their traditional lands by

competition from other land uses, such as sedentary agriculture.

• In some areas, the activities of nomadic pastoralists have also created

such environmental issues as desertification, hardening of topsoil,
and loss of soil fertility.

How agricultural practices alter the landscape

Agricultural Practices Alter the Landscape

Draining Wetlands

▪Wetland: Area of land that is covered by
water. Swamps, marshes & bogs.

▪Drained & converted to arable, farmland.

▫In the Netherlands, 17% of the
countries total land area was reclaimed
for farming and habitation.

▪Results in loss of biodiversity and other
environmental issues

▫Loss of habitat for fish, waterfowl, and
mammals.

▫Increases storm and flood damage

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In the Netherlands the creation of dikes (A dike is a barrier used to regulate or hold back water)
and polders (the term used to describe any piece of land reclaimed from water). Once dikes
were built, canals and pumps were used to drain the land and to keep it dry.

From the 1200s, windmills were used to pump excess water off the fertile soil, and windmills
became an icon of the country. Today, however, most of the windmills have been replaced with
electricity- and diesel-driven pumps.

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Draining wetlands

• Wetlands provide habitat for a wide range of species and are among

Earth’s most biologically productive and diverse ecological
communities.

• Because draining threatens wetlands species with extinction

worldwide, most countries now have regulations inhibiting further
wetland drainage.

How agricultural practices alter the landscape

Water control land reclamation: The process of draining land inundated
with either fresh water or salt water to increase areas for agricultural
production.

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Impacts on the landscape

How agricultural practices alter the landscape

• Vast areas of natural habitat and associated biodiversity are lost when

they are submerged by water held behind dams.

• Downstream, dams block fish from migrating to spawn and

reproduce. They also alter water quality, creating unlivable conditions
for many native aquatic species.

• The once-huge Aral Sea is now only a fraction of its size 40 years ago

due to large-scale irrigation. The rerouting of water from the rivers
flowing into it has created dry and exposed areas of the lakebed.

Multiple Choice

41-2Which central Asian body of water has shrunk drastically as a result of irrigation?

• a. the Aral Sea 

• b. the Dead Sea 

• c. the Red Sea 

• d. the Salton Sea 

• e. the Black Sea 

Multiple Choice

41-2 The marine biological crisis occurring today is a result of all of the following EXCEPT:

• a. water pollution 

• b. overfishing 

• c. habitat loss 

• d. increased demand for hydroelectric power 

• e. warming waters 

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Humans modify the physical

environment to suit their needs and
this shapes the cultural landscape.

Environmental Effects of Agriculture

Pollution

▪Increase in the demand for meat ->
increased animal waste -> Can contain
bacteria and nitrates which can contaminate
water sources, soil and cause illness.

▪Pesticide and herbicide -> chemicals into
the air, soil, and water -> runoff
contaminates water sources and damages
wildlife habitats.

▪Use of fossil fuels increase greenhouse
gases that contribute to climate change.
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Pollution: pesticides

• As much as 95 percent of pesticide spray may not reach its target but

instead is dispersed into the surrounding environment.

• Some pesticides kill all insects indiscriminately, including bees,

necessary for the pollination of many crops.

• Many pesticides have negative health effects on humans, including

hormone disorders, skin and neurological diseases, and cancers.

How agricultural practices and land use impact
the environment

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Pollution: agricultural runoff

• Pesticides may enter the larger environment in runoff from farms,

and may ultimately reduce aquatic and terrestrial biodiversity.

• Synthetic fertilizers also enter the environment through runoff from

cultivated farm fields or CAFOs (concentrated animal feeding
operations).

How agricultural practices and land use impact
the environment

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Nutrient pollution

• Nutrient pollution occurs when excess nutrients seep into groundwater

or are carried as runoff, which can result in algae blooms, sudden
spurts of algae growth that turn bodies of water green.

• Some algae blooms produce poisonous substances that kill animals,

raise the cost of treating water, and caused illnesses in humans who
swam in the water or ate tainted fish.

How agricultural practices and land use impact
the environment

Dead zones: Sections of a body of water where there is very little aquatic
life.

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Nutrient pollution

How agricultural practices and land use impact
the environment

Dead zones: Sections of a
body of water where there is
very little aquatic life.

Environmental Effects of Agriculture

Soil Salinization

▪The process by which salts build up in the
soil when water evaporates from the
ground more rapidly than it is replenished.

▪Salt interferes with the ability of plants to
absorb water and strips nutrients from the
soil.

▪Rapidly increasing as more land comes
under irrigation and wetlands are drained.

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Environmental Effects of Agriculture

▪Example: The Aral Sea in Central Asia

▫Rivers were diverted in the 1960s to
irrigate the desert regions for cotton
production.

▫Water levels declined, soil became
salinized (became salty) and fish died.

▫Changed the cultural landscape,
impacted the fishing economy.

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AS OF 2019, THE ARAL SEA IS 1/10 OF

ITS ORIGINAL SIZE

Environmental Effects of Agriculture

Deforestation

▪Tropical rainforests -> Amazon, and rainforests in
Indonesia and Malaysia.

▪Rising demand for has led to the conversion of
forests:

▫Logging Industry

▫Slash and burn subsistence farming

▫Cattle Grazing

▫Commercial Agriculture - Palm Oil

▪Results in increased greenhouse gas emissions,
soil erosion, loss of biodiversity
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Environmental Effects of Agriculture

Deforestation

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Land transformation

How agricultural practices and land use impact
the environment

Deforestation:
Clearing and
destruction of
forests to clear land
for agriculture use.

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Land transformation

How agricultural practices and land use impact
the environment

Deforestation:
Clearing and
destruction of
forests to clear land
for agriculture use.

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• Soil salinization is also a problem in the world’s arid regions, such as the

U.S. West, contributing to a change in the land cover from cropland to
barren ground.

How agricultural practices and land use impact
the environment

Desertification: The process by which once-fertile land becomes desert as
a result of climate variation or human activities.

Land transformation

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Conservation agriculture

• Individuals, groups, nations, and global organizations seek to minimize

soil disturbance and maximize species diversification.

• They also seek to create permanent soil organic cover, which is created

when crop residues are left on the ground or a crop is planted to hold
the soil until the next commercial crop is planted.

How agricultural practices and land use impact
the environment

Multiple Choice

41-1The creation of large amounts of arid land as a result of over-farming or overgrazing is called:

• a. intertillage 

• b. desertification 

• c. aridization 

• d. reverse irrigation 

• e. sustainable farming 

Multiple Choice

41-1 What is the primary driver of forest loss in Latin America? 

• a. soybean cultivation 

• b. timber harvesting for building 

• c. cattle ranches 

   

• d. palm oil plantations 

• e. expanding suburban areas of large cities

Multiple Choice

41-1 Which migrant group within the United States is exposed to high levels of harmful chemicals in pesticides and fertilizers? 

• a. Koreans 

• b. Vietnamese 

• c. Indians 

• d. Hispanics 

• e. Americans 

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Increases to agricultural

production have significantly
impacted the environment.

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Changing diets

• The globalization of agriculture and concern for health has led to

changes in diet in the industrialized world, including an increase in
chicken consumption and an increase in the consumption of fruits
and vegetables.

• Integrated networks of refrigeration systems and improvements in

transportation systems have permitted the shipping of perishable
fruits and vegetables across the world.

How changes in agricultural practices affect society

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Changes in women’s roles

• As farming becomes more mechanized, women’s roles change,

sometimes causing them to leave farms for work in nearby cities.

• In developing and developed countries, it is not unusual for women

to have different access to technology than men do.

How changes in agricultural practices affect society

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Changes in the uses of agricultural products

How changes in agricultural practices affect society

Biofuel: A fuel derived from organic wastes or plant materials.

Biodiesel: Fuel made from vegetable oils.

• Through the simple process of fermentation, many plant materials

(e.g., from corn) can be converted to a combustible alcohol, ethanol.

• Brazil, the closest international rival of the United States in ethanol

production, grows and ferments sugarcane, which yields twice as
many gallons of ethanol per acre as corn.

Multiple Choice

41-3 In the United States, which agricultural product is the main source of ethanol?

• a. wheat 

• b. sugarcane 

• c. corn 

• d. barley 

• e. soybeans 

Multiple Choice

41-3 The ethanol manufactured in Brazil is made from: 

• a. corn 

• b. sugarcane 

• c. wheat 

• d. olives 

• e. soybeans 

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Summary and Review

Pesticides, agricultural runoff, and nutrient
pollution

1) Identify sources of
pollution.

2) Describe types of negative
land transformation caused by
agricultural practices.

Deforestation, which is the clearing and
destruction of forests to clear land for
agriculture use. Desertification, which is
the process by which once-fertile land
becomes desert as a result of climate
variation or human activities. Soil
salinization, which may transform
cropland into barren ground.

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Individuals, groups, nations, and global
organizations seek to minimize soil
disturbance and maximize species
diversification and seek to create
permanent soil organic cover

3) Describe conservation
agriculture.

4) Identify agricultural
practices that alter the
physical landscape.

Shifting cultivation, paddy rice terraces,
nomadic pastoralism, draining wetlands,
irrigation, and construction of dams

Summary and Review

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Farming that relies on the controlled
application of water to cultivated fields
5) Define irrigated agriculture.

6) Define water mining.

The use of deep-well drilling technology
and powerful industrial pumping systems
to remove water in the ground

7) Explain how changes in
agricultural practices affect
diets.

There has been an increase in chicken
consumption and an increase in the
consumption of fruits and vegetables due
to refrigerated transportation systems

Summary and Review

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A fuel derived from organic wastes or
plant materials
8) Define biofuel.

9) Describe the process of
producing ethanol.

Through the simple process of
fermentation, many plant materials (e.g.,
from corn or sugar) can be converted to a
combustible alcohol, ethanol

Summary and Review