剑桥雅思13Test4阅读Passage2阅读文章SAVING THE SOIL保护土壤对应练习及解析,详见剑桥雅思13Test4阅读Passage2原文译文题目及答案解析全部内容介绍,希望帮助大家结合有效练习掌握雅思阅读考点。


  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 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 was to take care of the soil, and has developed a cocktail of beneficial bacteria, fungi and humus[ Humus: the part of the soil formed from dead plant material] 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, 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 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.





  来自纽约卡瑞生态系统研究所的Peter Groffman指出在几十年间,土壤科学家一直针对地球上的土壤退化现象发出警告。与此同时,我们归于土壤对人类重要性的理解也在提高。仅一克健康土壤中就可能含有一亿细菌,以及一些其他微生物,如病毒和真菌,他们存在于腐烂植物和各种矿物质中。这意味着土壤并不是只能用来种植食物,而是几乎所有现存抗生素的来源,并且可能是我们对抗耐药性细菌的最大希望。土壤同样可以帮助我们对抗气候变化:由于土壤中的微生物消化死去的动物和植物,他们可以留住动植物的碳成分,保存相当于整个大气层三倍的碳含量。土壤同样可以贮藏水分,防止洪水灾害:在英国,每年由于土壤退化而遭受洪灾的建筑物,道路和桥梁需要花费2.33亿英镑来修复。


  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 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 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