雅思阅读 96: The Return of the Tree in the Field（田垄间重新长出的树）

改编自 Frontiers in Sustainable Food Systems / MDPI Agriculture（2023–2025年）。雅思阅读 Section 3 难度，约 1050 词。 素材来源：https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2023.1234108/full

Reading Passage

A. For most of the past century, the efficient farm was the bare farm. Hedgerows were bulldozed, trees grubbed out, stubble burned and the soil left exposed between seasons, so that a single giant machine could sow, spray and harvest without obstruction. The model delivered cheap grain, but it paid a hidden price: every bare field is a field losing carbon. Tilling breaks apart the crumbs of soil, exposes organic matter to the air and lets it oxidise back into carbon dioxide; a century of such farming has stripped agricultural soils worldwide of perhaps a third of the carbon they once held, while eroding the living layer on which all farming ultimately depends. Regenerative agriculture is, in essence, the attempt to farm in the opposite direction — to treat the soil not as an inert growing medium but as a living sponge that can be built back up, sponge by sponge, drawing the same carbon back down from the atmosphere and, in the process, keeping more water on the land. The pitch is appealing to two audiences at once: farmers worried about erosion and drought, and governments hunting for any way to soak up the carbon their factories and cars refuse to give up.

B. The package of practices that goes by that name is broader than its marketing suggests. A 2023 analysis collated 345 measurements of soil carbon from crops and vineyards and sorted the techniques farmers actually use into seven families: agroforestry, cover cropping, legume cover crops, the integration of livestock, the avoidance of chemical fertilisers, the avoidance of chemical pest control, and no-till management. Each attacks the problem from a slightly different angle. No-till stops the plough from crumbling the soil; cover crops keep something growing on the land through the fallow months, feeding roots into the earth when the field would otherwise be bare; livestock put manure back where synthetic bags used to be. Taken together, they rest on a single principle: keep living roots in the ground, keep the soil covered, and disturb it as little as possible — so that the community of microbes and fungi living there is never uprooted. Where the old farm saw bare earth between harvests as honest efficiency, the new one sees it as an empty bank account.

C. What surprised the researchers was how evenly these techniques performed. Across all seven practices, the rate at which soils gained extra carbon was positive, and — notably — there was no statistically significant winner. A vineyard that simply stopped ploughing sequestered roughly as much, per hectare per year, as one that planted trees between its rows. This is inconvenient for anyone hoping for a silver bullet, but encouraging for farmers: it means the choice of technique can follow what suits the local climate, the budget and the existing machinery, rather than being dictated by a single best method. The analysis also hinted that combining practices stacked the benefits, so that a no-till field with a living cover crop and a few grazing animals did better than any one of them in isolation. The practical message is less glamorous than the advertisements: there are many roads to a darker, richer soil, and the ones a farmer can actually maintain year after year are usually the best. Critics of the marketing, in other words, can have their point without dismissing the underlying soil science; the practices work, but they work modestly and patiently, not as overnight magic.

D. Of the seven, agroforestry — the deliberate planting of trees and shrubs among the crops — has attracted particular attention, because trees do what annual crops cannot: they root deep. Where a wheat plant reaches down perhaps a metre, a tree roots many times deeper, pumping carbon into the subsoil where it is protected from disturbance, and dropping leaf litter on the surface that feeds the soil. Temperate agroforestry has been measured to lift microbial diversity in the topsoil by between fifteen and twenty-five per cent and to soften the most extreme surface temperatures by a degree or two. Yet the review literature is careful to flag trade-offs too: nitrogen-rich leaf litter can fertilise the wrong microbes and push up emissions of nitrous oxide, a far more potent greenhouse gas than carbon dioxide itself, and shaded, damp soils can in places encourage methane. There is no free lunch; the right tree in the right place is the difference between a sink and a source, and a species chosen purely for its growth rate may quietly cost more climate benefit than it stores.

E. The picture that emerges is therefore not the simple redemption story told in promotional brochures. Regenerative practices do reliably pull carbon down, but they do so slowly — over decades rather than seasons — and not without local downsides that demand careful management. Some of the carbon, it turns out, is locked away not by fallen leaves and roots directly but by the corpses of soil microbes, whose remains glue the soil together into stable crumbs. There is also no escaping the older virtue: a soil that holds more carbon holds more water, resists erosion and feeds a denser web of life. Whether the approach can be scaled across millions of hectares fast enough to matter for the climate remains an open question, and whether the carbon thus stored survives a drought or a bad season is still being measured. But the agronomic case that bare, exhausted soils are a design flaw rather than an inevitability now rests on a solid and growing body of evidence, and on that basis the bare field, like the bare riverbank, begins to look less efficient than it once did. Whether it can be done at the scale the climate demands is now as much a question of markets and policy as of soil science.

Questions 1-4

Choose the correct heading for paragraphs B, C, D and E from the list of headings below.

List of Headings i. The seven techniques farmers actually use ii. How ploughing releases soil carbon into the air iii. Why no single method clearly beats the others iv. Deep roots — and the hidden downsides of trees v. A measured verdict on the whole approach vi. The rise of the giant harvesting machine vii. Why synthetic fertilisers must always be banned

1. Paragraph B: ____
2. Paragraph C: ____
3. Paragraph D: ____
4. Paragraph E: ____

Questions 5-8

Choose the correct letter, A, B, C or D.

5. Why does the writer call the efficient twentieth-century farm "the bare farm"? A. Crops were harvested by hand. B. Hedgerows, trees and stubble were removed to ease mechanical farming. C. No irrigation was used in summer. D. The soil was left exposed only at harvest.

6. What did the 2023 analysis find about the seven practices? A. No-till was by far the most effective. B. All of them raised soil carbon, with no clear statistical winner. C. Cover cropping actually reduced carbon. D. They worked only in vineyards.

7. Why do agroforestry trees store carbon differently from wheat? A. They require no sunlight. B. They root much deeper, reaching carbon into the subsoil. C. They absorb carbon only through their leaves. D. They grow no roots at all.

8. What downside of nitrogen-rich leaf litter is flagged? A. It makes the soil too dry. B. It can raise emissions of nitrous oxide. C. It attracts too many grazing animals. D. It blocks all sunlight from the crops.

Questions 9-13

Do the following statements agree with the claims of the writer?

Write:

• TRUE if the statement agrees with the information
• FALSE if the statement contradicts the information
• NOT GIVEN if there is no information on this

9. Ploughing breaks up soil structure and releases organic matter as carbon dioxide.
10. The analysis found agroforestry sequestered significantly more carbon than no-till.
11. Combining several practices tended to add further benefits.
12. Regenerative soils typically recover their lost carbon within a single growing season.
13. Organic farms are always more profitable than conventional farms.

Questions 14-15

Complete the summary below using NO MORE THAN TWO WORDS from the passage.

Some soil carbon is locked away indirectly through the remains of soil (14) __________, whose dead material helps bind the soil; a carbon-rich soil also holds more (15) __________ and resists erosion.

答案与解析

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