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 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 antibioticresistant 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.
B来自纽约卡里生态系统研究所的 Peter groffman指出,数十年来,土壤科学家一直在警告人们土壤退化的问题。与此同时,我们也越来越认识到土壤的重要性。每克健康的土壤除了含有一些微生物如病毒和真菌外,还可能含有1亿个细菌,它们以分解植物和各种矿物质为生。
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.
D但随着人口的增长和农业逐渐变得商业化,这些做法越来越不可行了。直到20世纪早期,出现了一种新的解决方案——用哈伯-博斯制氨法( Haber-Bosch process制造氨硝酸。从那以后,农民们就在田地里施加这种合成肥料。
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* 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.
E有一个试图解决问题的人叫 Pius floris,他起初在荷兰经营树木护理业务,现在给数位顶级的土壤科学家提供咨询。他开始意识到使树木繁茂的一个重要条件是保护土壤,为了达成这个目标,他还开发了一种混杂有益细菌、真菌和腐殖质的物质。西班牙巴利亚多利德大学的研究者们最近把这种混合物施在了遭受多年化肥滥用的土壤中。在贫瘠的沙漠般的试验田里,他们施用了 floris的混合物后,结果长出了些长势良好的作物,不但表面上看起来很健康,而且它们发达的根系可穿透像岩石般坚硬的土壤。而在另一片对比试验田里,依然使用传统的化肥,植物看上去矮且虚弱。
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.
G但这只是解决问题的第一步。加拿大温尼伯国际可持续发展研究所的 PamelaChasek表示,我们需要想办法让政府和公众知晓问题的存在。他说:“对大多数科学家的说辞,决策者们并不买账,反过来也是这样。” Chasek及其同事们已经提出了一个目标,即“零土壤退化”。就像零碳排放的想法一样,这个目标更易于理解,可以帮助人们制订预期目标,鼓励人们采取行动。