READING
READING
PASSAGE 2
You should spend about 20 minutes on
Questions 14-26, which are based on Reading
Passage 2 below.
SAVING THE SOIL
More than a
third of the Earth’s top layer is at risk. Is there hope for our planet’s
most precious resource?
|
|
A
|
More than a
third of the world’s soil is endangered, according to a recent UN report. If we
don’t slow the decline, all farmable soil could be gone in 60 years. Since soil
grows 95% of our food, and sustains human life in other more surprising ways,
that is a huge problem.
|
B
|
Peter Groffman,
from the Cary Institute of Ecosystem Studies in New York, points out that
soil scientists have been warning about the degradation of the world’s soil
for decades. At the same time, our understanding of its importance to humans
has grown. A single gram of healthy soil might contain 100 million bacteria,
as well as other microorganisms such as viruses and fungi, living and
decomposing plants and various minerals.
That means
soils do not just grow our food, but are the source of nearly all our
existing antibiotics, and could be our best hope in the fight against
antibiotic-resistant bacteria. Soil is also an ally against climate change;
as microorganisms within soil digest dead animals and plants, they lock in
their carbon content, holding three times the amount of carbon as does the
entire atmosphere. Soils also store water, preventing flood damage; In the
UK, damage to buildings, roads and bridges from floods caused by soil
degradation costs £233 million every year.
|
C
|
If the soil
loses its ability to perform these functions, the human race could be in big
trouble. The danger is not that the soil will disappear completely, but that
the microorganisms that give it its special properties will be lost. And once
this has happened, it may take the soil thousands of years to recover.
Agriculture is
by far the biggest problem. In the wild, when plants grow they remove
nutrients from the soil, but then when the plants die and decay these
nutrients are returned directly to the soil. Humans tend not to return unused
parts of the harvested crops directly to the soil to enrich it, meaning that
the soil gradually becomes less fertile. In the pass we developed strategies
to get around the problem, such as regularly varying the types of crops
grown, or leaving fields uncultivated for a season.
|
D
|
But these
practices became inconvenient as populations grew and agriculture had to be
run on more commercial lines. A solution came in the early 20th
century with the Haber-Bosch process for manufacturing ammonium nitrate. Farmers
have been putting this synthetic fertiliser on their fields ever since.
But over the
past few decades, it has become clear this wasn’t such a bright idea. Chemical
fertilisers can release polluting nitrous oxide into the atmosphere and
excess is often washed away with the rain, releasing nitrogen into rivers. More
recently, we have found that indiscriminate use of fertilisers hurts the soil
itself, turning it acidic and salty, and degrading the soil they are supposed
to nourish.
|
E
|
One of the
people looking for a solution to this problem is Pius Floris, who started out
running a tree-care business in the Netherlands, and now advises some of the
world’s top soil scientists. He came to realise that the best way to ensure
his trees flourished to take care of the soil, and has developed a cocktail
of beneficial bacteria, fungi and humus* to do this. Researchers at the
University of Valladolid in Spain recently used this cocktail on soils
destroyed by years of fertiliser overuse. When they applied Floris’s mix to
thhe desert-like test plots, a good crop of plants emerged that were not just
healthy at the surface, but had roots strong enough to pierce dirt as hard as
rock. The few plants that grew in the control plots, fed with traditional
fertilisers, were small and weak.
|
F
|
However,
measures like this are not enough to solve the global soil degradation
problem. To assess our options on a global scale we first need an accurate
picture of what types of soil are out there, and the problems they face. That’s
not easy. For one thing, there is no agreed international system for
classifying soil. In an attempt to unify the different approaches, the UN has
created the Global Soil Map project. Researchers from nine countries are
working together to create a map linked to a database that can be fed
measurements from field surveys, drone surveys, satellite imagery, lab
analyses and so on to provide real-time data on the state of the soil. Within
the next four years, they aim to have mapped soils worldwide to a depth of
100 metres, with the results freely accessible to all.
|
G
|
But this is
only a first step. We need ways of presenting the problem that bring it home
to governments and the wider public, says Pamela Chasek at the International
Institute for Sustainable Development, in Winnipeg, Canada. ‘Most scientists don’t
speak language that policy-makers can understand, and vice versa.’ Chasek and
her colleagues have proposed a goal of ‘zero net land degradation’. Like the
idea of carbon neutrality, it is an easily understood target that can help
shape expectations and encourage action.
For soils on
the brink, that may be too late. Several researchers are agitating for the
immediate creation protected zones for endangered soils. One difficulty here
is defining what these areas should conserve; areas where the greatest soil
diversity is present? Or areas of unspoilt soils that could act as a future
benchmark of quality?
Whatever we do,
if we want our soils to survive, we need to take action now.
|
Questions
14-17
Complete
the summary below
Choose
ONE WORD ONLY from the passage for
each answer.
Write
your answers in boxes 14-17 on your answer sheet.
Why soil degradation could be a
disaster for humans
|
Healthy soil
contains a large variety of bacteria and other microorganisms, as well as
plant remains and 14 __________. It provides us with food and also with antibiotics,
and its function in storing 15 __________ has a significant effect on the
climate. In addition, it prevents damage to property and infrastructure
because it holds 16 __________.
If these
microorganisms are lost, soil may lose its special properties. The main
factor contributing to soil degradation is the 17 __________ carried out by humans.
|
Questions
18-21
Complete
each sentence with the correct ending, A-F,
below.
Write
the correct letter, A-F, in boxes
18-21 on your answer sheet.
18
|
Nutrients contained in the unused
parts of harvested crops.
|
19
|
Synthetic fertilisers produced with
the Haber-Bosch process.
|
20
|
Addition of a mixture developed by Pius Floris to the
soil.
|
21
|
The Idea of zero net soil
degradation.
|
A
|
may improve the number and quality of plants growing
there.
|
B
|
may contain data from up to nine countries.
|
C
|
may
not be put back into the soil.
|
D
|
may help governments to be more aware of soil-related
issues.
|
E
|
may
cause damage to different aspects of the environment.
|
F
|
may be better for use at a global level.
|
Questions 22-26
Reading Passage 2 has seven paragraphs, A-G.
Which section contains the following information?
Write the correct letter, A-G, in boxes 22-26 on your answer sheet.
NB You may use any letter more than once.
22
|
a reference to one’s motivation for a soil-improvement
project.
|
23
|
an explanation of how soil stayed healthy before the
development of farming.
|
24
|
examples of different ways of collecting information on
soil degradation.
|
25
|
a suggestion for a way of keeping some types of soil in
the near future.
|
26
|
a reason why it is difficult to provide an overview of
soil degradation.
|
ANSWER KEY
14
|
minerals
|
15
|
carbon
|
16
|
water
|
17
|
agriculture
|
18
|
C
|
19
|
E
|
20
|
A
|
21
|
D
|
22
|
E
|
23
|
C
|
24
|
F
|
25
|
G
|
26
|
F
|
No comments:
Post a Comment
thank you for visiting my blog and for your nice comments