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 amid 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 harvested crops directly to the soil to enrich it, meaning that the soil gradually becomes less fertile. In the past 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 his 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 was 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 the 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, lad 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 of 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.
Write 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 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 person’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 safe in the near future
26. a reason why it is difficult to provide an overview of soil degradation
LỜI GIẢI CHI TIẾT
Question 14. HEALTHY SOIL CONTAINS A LARGE VARIETY OF BACTERIA AND OTHER MICROORGANISMS, AS WELL AS PLANT REMAINS AND……………
Keywords: healthy, bacteria, microorganisms, plant remains
Now, we need to find information on the contents of healthy soil, using the key words. We find these words in the first part of paragraph B: “A single gram of healthy soil might contain 100 million bacteria, as well as other microorganisms such as viruses and fungi, living amid decomposing plants and various minerals”.
Thus, we have a list of the things which healthy soil contains – bacteria, microorganisms, plant remains and minerals.
Here, plant remains = decomposing plants.
Answer: minerals.
Question 15. IT PROVIDES US WITH FOOD AND ALSO WITH ANTIBIOTICS, AND ITS FUNCTION IN STORING …………… HAS A SIGNIFICANT EFFECT ON THE CLIMATE.
Keywords: food, antibiotics, storing, climate
Now, the second part of paragraph B gives us the answer: “…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”.
In other words, soil holds carbon, preventing its release into the atmosphere and so helping to prevent global warming.
Here, provides us with ~ are the source of; store = lock in; a significant effect on the climate ~ an ally against climate change.
Answer: carbon.
Question 16. IN ADDITION, IT PREVENTS DAMAGE TO PROPERTY AND INFRASTRUCTURE BECAUSE IT HOLDS …………….
Keywords: prevents, damage, property and infrastructure, holds
Continuing to look for key words in paragraph B, we find the answer: “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”.
Soils hold water. This reduces the problem of flooding and the damage which is caused by flooding.
Here, hold = store; buildings, roads and bridges = property and infrastructure.
Answer: water.
Question 17. THE MAIN FACTOR CONTRIBUTING TO SOIL DEGRADATION IS THE ……………… CARRIED OUT BY HUMANS
Keywords: main factor, degradation, humans
We find the answer in paragraph C: “Agriculture is by far the biggest problem……Humans tend not to return unused parts of harvested crops directly to the soil to enrich it, meaning that the soil gradually becomes less fertile”.
So, agriculture is the biggest problem. The way that it is practiced/carried out means that the soil becomes less fertile.
Here, main factor = biggest problem; soil degradation = the soil gradually becomes less fertile.
Answer: agriculture.
QUESTIONS 18-21: COMPLETE EACH SENTENCE WITH THE CORRECT ENDING, A-F
Question 18. NUTRIENTS CONTAINED IN THE UNUSED PARTS OF HARVESTED CROPS
Keywords: nutrients, unused, harvested crops
Now, we find these key words in the second part of paragraph C: “…when the plants die and decay these nutrients are returned directly to the soil. Humans tend not to return unused parts of harvested crops directly to the soil to enrich it, meaning that the soil gradually becomes less fertile”.
Ending C gives us the following sentence: ‘Nutrients contained in the unused parts of harvested crops may not be put back into the soil’.
Here, may not be put back = tend not to return
Answer: C.
Question 19. SYNTHETIC FERTILISERS PRODUCED WITH THE HABER-BOSCH PROCESS
Keywords: synthetic fertilisers, Haber-Bosch
Now, paragraph D contains these key words: “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.”
Continuing to read, we find out the problems of using these synthetic fertilisers: “Chemical fertilisers can release polluting nitrous oxide into the atmosphere and excess is often washed away with rain, releasing nitrogen into rivers. More recently, we have found that indiscriminate use of fertilisers hurts the soil itself, turning it acidic and salty…”
Ending E gives us the following sentence: ‘Synthetic fertilisers produced with the Haber-Bosch process may cause damage to different aspects of the environment’. These different aspects are the atmosphere, rivers and the soil.
Here, damage = hurt.
Answer: E.
Question 20. ADDITION OF A MIXTURE DEVELOPED BY PIUS FLORIS TO THE SOIL
Keywords: addition, mixture, Pius Floris
Now, the name Pius Floris is mentioned in paragraph E. He “…developed a cocktail of beneficial bacteria, fungi and humus”.
Researchers then “…used this cocktail on soils destroyed by years of fertiliser overuse. When they applied Floris’s mix to the desert-like 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”.
Ending A gives us the following sentence: ‘Addition of a mixture developed by Pius Floris to the soil may improve the number and quality of plants growing there’.
This is exactly what took place on the plots (= the soil) to which Floris’s mixture/mix was added – more plants grew there, and the plants were stronger.
Here: mixture = cocktail.
Answer: A.
Question 21. THE IDEA OF ZERO NET SOIL DEGRADATION
Keywords: idea, zero, degradation
now, in paragraph G, we find a reference to ‘zero net land degradation’. It is a goal which policy- makers can easily understand, like “…the idea of carbon neutrality”. Scientists have therefore proposed this goal to “…shape expectations and encourage action”: “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”. Ending D gives us the following sentence: ‘The idea of zero net soil degradation may help governments to be more aware of soil-related issues”.
Here, be more aware of soil-related issues = bring the problem home to governments.
Answer: D.
Question 22. A REFERENCE TO ONE PERSON’S MOTIVATION FOR A SOIL-IMPROVEMENT PROJECT
Keywords: motivation, soil-improvement project
Now, in paragraph E, Pius Floris is mentioned. His motivation to improve the soil came from “…running a tree-care business in the Netherlands”. The writer tells us that: “He came to realise that the best way to ensure his trees flourished was to take care of the soil, and has developed a cocktail of beneficial bacteria, fungi and humus to do this”.
Therefore, the ‘one person’ referred to is Pius Floris.
Answer: E.
Question 23. AN EXPLANATION OF HOW SOIL STAYED HEALTHY BEFORE THE DEVELOPMENT OF FARMING
Keywords: explanation, soil, healthy, before, farming
Now, in paragraph C: “Humans tend not to return unused parts of harvested crops directly to the soil to enrich it, meaning that the soil gradually becomes less fertile. In the past we developed strategies to get around the problem, such as regularly varying the types of crops grown, or leaving fields uncultivated for a season”.
So, two different strategies are described to explain how – before farming became very developed – the problem of keeping the soil healthy was solved.
Answer: C.
Question 24. EXAMPLES OF DIFFERENT WAYS OF COLLECTING INFORMATION ON SOIL DEGRADATION
Keywords: ways, collecting information, soil degradation
Now, in paragraph F, we learn that: “…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”.
Several different ways of collecting information (measurements) are given as examples of ways to determine the state of the soil, and how much it has been degraded.
Here, information = real-time data
Answer: F.
Question 25. A SUGGESTION FOR A WAY OF KEEPING SOME TYPES OF SOIL SAFE IN THE NEAR FUTURE
Keywords: soil, safe, near future
Now, in the final paragraph, we find the following statement: “Several researchers are agitating for the immediate creation of protected zones for endangered soils”.
The suggestion of the researchers is to keep some soil types safe by creating protected zones.
Here, keeping some types of soil safe = creation of protected zones; the near future = immediate.
Answer: G.
Question 26. A REASON WHY IT IS DIFFICULT TO PROVIDE AN OVERVIEW OF SOIL DEGRADATION
Keywords: difficult, overview, soil degradation
Now, we find the answer in paragraph F: “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”.
Therefore, we need to have an accurate picture of soil types and the dangers to them. The reason that is difficult is that we have no agreed way of doing this.
Here, overview = accurate picture; difficult = not easy; a reason = for one thing.
Answer: F.
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