Tiếng anh chuyên ngành Thổ nhưỡngvà Môi trường đất
NXB Đại học quốc gia Hà Nội 2007.
Tr 120 – 130.


Tài liệu trong Thư viện điện tử ĐH Khoa học Tự nhiên có thể được sử dụng cho
mục đích học tập và nghiên cứu cá nhân. Nghiêm cấm mọi hình thức sao chép, in
ấn phục vụ các mục đích khác nếu không được sự chấp thuận của nhà xuất bản và
tác giả.


Mục lục

Unit 13 SOIL EROSION 2
A. Reading 2
I. Comprehension questions 3
II. True-False sentences 4
III. Increasing your vocabulary 4
B. WRITING 5
I. Sentence - building 5
II. Sentence – transforming 6
C. FURTHER PRACTICE 7
D. TRANSLATION 9
I. Translate into Vietnamese 9
II. Translate into English 10
E. VOCABULARY 11

Unit 13. SOIL EROSION

Nguyễn Thị Minh Nguyệt
Unit 13
SOIL EROSION
A. Reading
• Warm-up Activities
- What are the causes of soil erosion?
- What should be done to prevent the soil from erosion?

Soil erosion is the movement of soil components, especially surface-litter and
topsoil, from one place to another. The two main movers are flowing water and wind.
Although wind causes some erosion, most is caused by moving water.
Some soil erosion is natural, but the roots of plants generally anchor the soil. In
undisturbed vegetated ecosystems, soil is not usually lost faster than it forms. However,
farming, logging, building, overgrazing by livestock, fire, and other activities that destroy
plant cover leave soil vulnerable to erosion.
Losing topsoil makes a soil less fertile and less able to hold water. The resulting
sediment, the largest source of water pollution, clogs irrigation ditches, boat channels,
reservoirs, and lakes. Fish die. Water is cloudy and tastes bad. Flood risk increases.
Soil, especially topsoil, is classified as a potentially renewable resource because it is
continuously regenerated by natural processes. However, in tropical and temperate areas it
takes 200-1.000 years for 2.54 centimeters (1 inch) of new topsoil to form, depending on
climate and soil type. If topsoil erodes faster than it forms on a piece of land, the soil there
becomes a non-renewable resource. Annual erosion rates for farmland throughout the
world are 7-100 times the natural renewal rate. Soil erosion is milder on forestland and
rangeland that on cropland, but forest soil takes two to three times longer to restore itself
than does cropland. Construction sites usually have the highest erosion rates by far.

Today topsoil is eroding faster than it forms on about one-third of the world's
cropland. A 1992 study by the World Resources Institute found that soil on more than 12
million square kilometers (5 million square miles) of land - an area the size of China and
India combined - had been seriously eroded since 1945. The study also found that 89,000
square kilometers (34,000 square miles) of land scattered across the globe was too eroded
to grow crops anymore. Overgrazing is the worst culprit, accounting for 35% of the
damage, with the heaviest losses in Africa and Australia. Deforestation causes 30% of
Earth's severely eroded land and is most prevalent in Asia and South America.
Unsustainable methods of farming cause 28% of such erosion, with two-thirds of the
damage found in North America.
Each year we must feed more 90 million people with an estimated 24 billion metric
tons (26 billion tons) less topsoil. This topsoil washing and blowing into the world's
streams, lakes, and oceans each year would fill a train of freight cars long enough to
encircle the planet 150 times. The situation is worsening as many farmers in LDCs plow
easily erodible lands to feed themselves.
(Taken from "Sustaining the Earth" by Tyler Miller, G. )
I. Comprehension questions
Answer the following questions
1. What cause soil erosion?


2. In which ecosystem is soil formation faster than its loss?


3. How do farming, logging, building, overgrazing and other activities affect the soil?


4. What can make a soil less fertile and less able to hold water?



5. What is the largest source of water pollution?




6. Why is topsoil classified as a potentially renewable resource?


7. How long does it take to form 1 inch of new topsoil in tropical and temperate
regions? What does it depend on?


8. What happens when topsoil erodes faster than it forms on a piece of land?


9. What are annual erosion rates for farmland all over the world?


10. What did the World Resource Institute find in its study?


II. True-False sentences
Decide whether the following statements are true "T", false "F" or there’s no
information given "N" according to the text. Correct the false sentences.
1. Surface-litter and topsoil are two main components of soil when soil erosion
occurs.
2. Farming and logging are two most serious ways making soil vulnerable to
erosion.
3. Losing topsoil is a cause that makes flood risk increases.
4. It takes decades to form 1 inch of new topsoil in tropical and temperature area.

5. The soil becomes a non-renewable resource if topsoil erodes faster than it
forms on a piece of land.
6. Soil erosion on forestland is the most serious.
7. Restoring cropland takes much more time than restoring forestland.
8. In 1992, about 89,000 square kilometers of land on earth was so eroded that
people couldn't grow crops.
9. Enough topsoil erodes away each day in the United Stated to fill a line of
dump trucks 5,600 kilometers (3,500 miles) long.
10. Unsustainable methods of farming account for 30% of soil erosion every year.
III. Increasing your vocabulary
Synonyms: Refer back to the text and find synonyms for the following
words/phrases:
1. destroy gradually
2. not disturbed
3. animals on farm
4. matter deposited on the land by water or wind
5. supply with water
6. generate again
Word-form: Use your dictionary to complete the table with the appropriate forms of
the given words in the text. The first is done as an example.

Noun Verb Adjective Adverb
1. Beauty beautify beautiful beautifully
2. erosion …………… …………… ……………
3. ……………
…
…………… …………… especially
4. movement …………… …………… ……………
5. …………… …………… natural ……………
6. …………… …………… …………… potentially

7. deforestation …………… …………… ……………
8. …………… …………… vulnerable ……………
9. …………… regenerate …………… ……………
10. …………… …………… mild ……………
B. WRITING
I. Sentence - building
Make necessary changes and additions to complete the passage from the prompts
below:
1. Vanishing topsoil / creeping desertification / be / still / serious problems / parts / United
States.


2. Today / soil / cultivated land / United States / be / eroding / about 16 times faster / it /
can form.


3. And / erosion rates / be / even higher / heavily farmed regions.


4. Parts / the Western rangelands / the Great Plains / be / undergoing / desertification /
from / overcultivation / overgrazing / and depletion of groundwater / which / be / use /
irrigation.


5. Some / country's most productive agricultural lands / have / lose / about / half their
topsoil.


6. California's soil / be / eroding / 80 times / than / it / can / form.



II. Sentence – transforming
Finish each of the following sentences in such a way that it means the same as the
sentence printed before it:
7. Topsoil is continuously regenerated by natural processes.
Natural processes


8. Today topsoil is eroding faster than it forms on about one-thirds of the world's
cropland.
Today topsoil forms


9. Soil erosion is milder on forestland and rangeland than on cropland.
Soil erosion on cropland


10. In 1935 the United States established the Soil Conservation Service under the
Department of Agriculture.
1935 is


11. People estimate that salinization is reducing yields on one-fourths of the world's
irrigated cropland.
It


C. FURTHER PRACTICE
Exercise 1: Gap-filling
Choose one of the words below to fill in each gap in the following passage. Each

word is used once only.
that amounts more growth scheme
process production they soil wet
also an it quantities out
be qualities salts produce to
Salts can be flushed (1) of soil by applying much (2)
irritation water than is needed for crop (3) , but this practice increases
pumping and crop-production costs, and (4) wastes enormous
(5) of water.
Heavily salinized (6) can also be renewed by taking the land out of
(7) for two to five years, installing (8) underground network of
perforated drainage pipes, and flushing the soil with large (9) of low-salt water.
This costly (10) , however, only slows the salt buildup, it does not stop the
(11) . Flushing (12) from the soil (13) makes down-
stream irrigation water saltier unless the saline water can (14) drained into
evaporation ponds rather than returned (15) the stream or canal.
Exercise 2: Study the following short passage and complete the statements about
them below:
1. The colors of soils is closely related to their condition of aeration. In well-drained soils
iron compounds are oxidized to their ferric state, which is indicated by reds, yellows
and browns. When good drainage is absent, soils tend to be gray, often with greenish
gray or mottled sub-soils.
Write less, more, better or poorer in the spaces provided:
a. A red soil is drained than a gray soil.
b. A gray soil has been oxidized than a yellow soil.
c. Greenish soils are well-drained than brown soils.
d. A red soil has conditions of aeration than a grey soil.
e. Well-drained soils are aerated than badly drained soils.
f. Grey and greenish soils have drainage than oxidized red soils.
g. There is air in a well-drained soil than in a badly drained soil.

2. The soil microbes which decompose organic materials grow best at pH 6.5. Near this
pH, conditions are best for the availability of most plant nutrients. As the acidity
increases, the availability of nearly all important nutrients diminishes. Phosphorous, in
particular, is held as insoluble compounds in highly acid soils. As acidity decreases
iron, manganese, copper and zinc grow scarce. Most upland soils developed under
forests in humid regions are too acid for the best growth of pasture grasses, vegetables
and many other plants.
Write less , more, fewer, not as good or higher in the spaces provided:
a. At a pH value of below 4 there are important nutrients in the soil.
b. There is soluble phosphorous in highly acid soils.
c. Iron, manganese, copper and zinc are available in
alkaline soils.
d. Vegetables prefer conditions of acidity than is found in most upland
soils.
e. Conditions are for the decomposition of organic materials by soil
microbes at low pH soil values.
D. TRANSLATION
I. Translate into Vietnamese
1. The costs of soil erosion may be divided into direct (on-site) or indirect (off-site).
The main direct cost is a decline in crop productivity. Indirect costs include
siltation of reservoirs, canals, streams (with associated loss of water supplies,
power generation capacity, flooding, increased dredging costs, etc), land-slide
damage to roads, infrastructure and housing. The direct costs are vast; the indirect
costs may also be and sometimes exceed on-site impacts (many large and smaller
hydropower and irrigation projects have been ruined by soil erosion). Soil
contributes considerably to the value of land; once soil degradation begins, land
values generally fall; ultimately the result may be virtually worthless, unsaleable
wasteland. Slight or moderate degradation may be sufficient to restrict what can be
grown (due to insufficient depth of soil or poor quality soil); it may also, by
reducing available soil moisture, reduce the land's resistance to drought.

(Taken from "Environmental Sciences" by Wilson, R)
2. Soil pollution damages the thin layer of fertile soil that covers much of the earth’s
land and is essential for growing food. Natural processes took thousands of years to
form the soil that supports crops. But, through careless treatment, people can
destroy soil in a few years. In nature, cycles similar to those that keep water clean
work to keep soil fertile. Plant and animal wastes, including dead organisms,
accumulate in the soil. Bacteria and fungi decay these wastes, breaking them down
into nitrates, phosphates, and other nutrients. The nutrients feed growing plants,
and when the plants die the cycle begins again. People use fertilizers and pesticides
to grow more and better crops. Fertilizers add extra nutrients to the soil and
increase the amount of a crop that can be grown on an area of land. But the use of
large amounts of fertilizer may decrease the ability of bacteria to decay wastes and
produce nutrients naturally. Pesticides destroy weeds and insects that harm crops.
But pesticides may also harm bacteria and other helpful organisms in the soil.
Much damage to soil results from erosion. Erosion is the wearing away of soil. It
can result from the removal of trees, grass, and other plants that hold soil in place.
Wind can then blow the bare soil away and rain can wash it away. Careless farming
methods are major cause of erosion. The clearing of land for construction projects
such as roads and real estate developments, also cause erosion.
(Taken from "English-Vietnamese Translation Materials for Advanced Students of
English" by Alan Mc Gowan and Jack W. Hudson)
II. Translate into English
3. Sự bảo tồn đất liên quan đến việc giảm sự xói mòn đất, ngăn không để các chất
dinh dưỡng trong đất bị cạn kiệt và khôi phục lại những chất dinh dưỡng đã mất đi
do sự xói mòn, do rửa trôi và do trồng trọt quá nhiều.




4. ở những miền đất thấp vùng nhiệt đới, hoạt động chặt phá gỗ là nguyên nhân chính

của sự xói mòn đất. Nhiều khu vực rộng lớn trên thế giới phải chịu sự suy thoái của
đất do hậu quả của việc sản xuất đường, thuốc lá và lạc.




5. Nông nghiệp có thể dẫn đến sự thiệt hại của đất qua sự xói mòn và nó rơi vào tình
trạng kém năng suất do hậu quả của sự ô nhiễm, sự muối hoá, sự ngập úng và nhiều
quá trình khác. Sự suy thoái của đất là một trong những vấn đề lớn trên toàn cầu. Ví
dụ, ở Mỹ khoảng 1/3 đất trồng hoa màu bị ảnh hưởng nghiêm trọng. Một vài thiệt
hại do tự nhiên hoặc do con người gây ra là điều khó tránh khỏi nhưng phần lớn lại
là hậu quả của các biện pháp bảo tồn đất không thích hợp.







E. VOCABULARY
1. annually (adj) : hàng năm
2. classify (v) : phân loại
3. cloudy (adj) : vẩn đục
4. component (n) : phần hợp thành
5. creeping desertification (n) : sự sa mạc hoá dần dần
6. cropland (n) : đất trồng trọt
7. culprit (n) : tội phạm, thủ phạm
8. cultivated land (n) : đất canh tác
9. ditch (n) : đường hào, rãnh
10. encircle (v) : vòng quanh, bao quanh

11. erode (v) : xói mòn
12. generally (adv) : dần dần
13. heavily farmed land (n) : vùng đất trồng trọt/canh tác nhiều
14. livestock (n) : vật nuôi
15. log (n) : gỗ
16. microbe (n) : vi sinh vật
17. overgrazing (n) : sự chăn thả quá mức
18. prevalent (adj) : thịnh hành, chiếm ưu thế
19. reservoir (n) : hồ chứa nhân tạo
20. risk (n) : rủi ro
21. salt (n) : muối
22. salty (adj) : mặn, có chứa muối
23. saline (adj) : mặn, có tính chất như muối
24. scatter (v) : phân tán
25. soil degradation (n) : sự suy thoái đất
26. temperate (adj) : ôn hoà
27. undisturbed (adj) : không bị xáo trộn, ổn định
28. vegetate (v) : sống đời sống thực vật
29. vulnerable (adj) : dễ bị tổn thương, dễ nhạy cảm