雅思阅读真题（Part 3）
澳大利亚土壤盐碱化危机与高科技治理
本篇也叫：土壤盐碱化、土地盐碱化、盐碱地、土壤盐渍化、澳洲盐碱化、盐害
Part 3 · 考频：中频 · 最近考试：2023.6.22/2017.2.25
本篇为雅思阅读真题（Part 3）《Sea change for salinity》，共 14 题，2023.6.22/2017.2.25雅思考试真题回忆，页面提供完整原文、题目、答案与解析，并支持在线机考模式免费练习。本页同时提供 Markdown 版本 供 AI 助手与搜索引擎直接读取。
文章讲述澳大利亚农民面临土壤盐分升高的严重问题，盐分像隐形杀手般侵蚀土地。地质学家利用航空电磁法等高科技手段探测地下盐分并预测其移动，农民如Angus Howell也参与治理，但盐碱化仍难以根治，涉及技术、社会与经济多重挑战。
One of the most serious problems facing Australian farmers is an increase in the salt content in the soil. However, there are new weapons emerging in the fight against salinity.
A
Beneath the flat, impassive surface of Australia lie hidden mountains, valleys and gorges - ancient traps and channels for the deadly salt that is stealthily killing so much of the Australian landscape. The war on salt is calling forth new weapons. A suite of high technologies used by geologists to see underground and prospect for gold and minerals is now being used to pinpoint the presence of salt beneath the landscape, and predict where it might move.
B
Unless this process is clearly understood, warns Chief of Exploration and Mining Dr Neil Phillips, the hard work now underway of planning and tree-planting on the surface may be rendered ineffective: salt can still sneak past and erupt, following one of the ancient river channels formed millions of years ago. The use of airborne electromagnetic to detect salt hidden beneath the landscape has been around for a decade, but the past two years have seen a major development in its precision and powers of detection. Like the use of radar in battles, it has the potential to turn the tide of the struggle in favour of the defence by helping to pinpoint, plot and predict the movements of the foe.
C
Angus Howell, who farms near Warrenbayne, in Southeast Australia, saw his first outbreak of salt in 1948. Over the ensuing decades the patches spread and multiplied until they consumed almost 100 hectares. By the late 1970s, Howell and his fellow farmers had decided it was time for action and established a government-funded "Landcare' group in a bid to save Australia's farmland. But despite a mounting effort by scientists, farmers and governments, the 'white death' continued to encroach. Small successes were eclipsed by larger defeats and fresh outbreaks.
D
‘The technical solutions just aren't there yet for dealing with broadacre salinity, nor are the social and economic solutions. How do you introduce the land-use changes that are needed when people still need to make a living?' Howell asks. There is no satisfactory solution yet. Part of the problem has lain in salt's ability to mount ambushes, emerging somewhere new, sometimes unexpected and unexplained, beating plans to intercept it. Only now are scientists starting to really disclose its secret subterranean stores and passages.
E
The need for such knowledge is pressing. Salt has already afflicted six million hectares of once-productive country. At present rates it is predicted that, by 2050. it will have sterilised a total of 17 million hectares and the waters of Australia's Murray River will regularly exceed the World Health Organisation's salt limits for drinking water. Defeating this assault may take centuries, not decades.
F
Electromagnetic surveys measure the electrical conductivity of soil to reveal the distribution of salt and the nature and variability of the regolith - the weathered rock and sediment that may lie above the bedrock. Magnetic surveys measure small differences in the Earth's magnetic field, enabling scientists to probe the deep past and reconstruct ancient landscapes - rivers, basins and faults now buried under tens of metres of sediments. These features help to reveal where groundwater is stored, dictate the direction of groundwater movement, and are critical to predicting or ruling out salinity hot-spots.
G
Radiometric analysis is based on the detection of radiation emitted by elements contained in rocks and soils, allowing scientists to delineate landforms. These factors influence the mobility of salt through the soil profile and help determine where to plant particular crop species to tackle the problem.
Using data from the Murray River region, scientists have revealed a network of ancient drainage channels buried metres beneath the current landscape. These buried channels may carry salt and sometimes run at right angles to channels on the surface. This implies that the salt could move underground in quite a different direction to what one would expect by looking at surface slope and drainage.
H
One of the biggest advances in detection, says Professor Neil Phillips, has come with the integration of different techniques such as magnetics, electromagnetics and radiomagnetics, and ground mapping. Individually, these technologies only gave clues to what was going on underground. Together they provide a far more revealing picture of the subsurface landscape, several hundred metres deep.
I
Advanced airborne electromagnetics, in particular, enables scientists to take ‘slices’ of the landscape at depths of five metres, ten metres, fifteen metres and so on, to determine where salt may be stored at depth. This is building up a four-dimensional picture of the subsurface landscape, enabling researchers to understand movements of salt in width, depth, breadth and time.
J
From such technologies it will be possible to locate salt stores, identify how saline they are, look at man-made and natural changes to the landscape that may cause it to mobilise, and then predict where it will head to and over what time span. This in turn will give the salt warriors time to model various ways of containing or curbing the menace, see what works best and then try it out on the ground.
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答案：E
原文定位：At present rates it is predicted that, by 2050;the waters of Australia's Murray River will regularly exceed the World Health Organisation's salt limits for drinking water
同义替换：「water supplies 」↔「drinking water」
答案：H
原文定位：Individually, these technologies only gave clues to what was going on underground. Together they provide a far more revealing picture of the subsurface landscape
同义替换：「combined」↔「together」，「to be effective」↔「far more revealing picture」，「reason why」↔「Individually, these technologies only gave」
答案：B
原文定位：The use of airborne electromagnetic to detect salt hidden beneath the landscape has been around for a decade, but the past two years have seen a major development in its precision and powers of detection
同义替换：「recent improvements」↔「past two years have seen a major development」，「accuracy」↔「precision」
答案：C
原文定位：By the late 1970s, Howell and his fellow farmers had decided it was time for action and established a government;funded "Landcare' group in a bid to save Australia's farmland;
同义替换：「organization」↔「established」，「official body」↔「government-funded group」
答案：E
原文定位：Defeating this assault may take centuries, not decades
同义替换：「estimated length of time」↔「take centuries」，「salinity is likely to be a problem」↔「defeating this assault」
答案：H
原文定位：One of the biggest advances in detection;has come with the integration of different techniques;Together they provide a far more revealing picture of the subsurface landscape
同义替换：「stages in a proposed plan」↔「integration of different techniques」，「combat the salt problem」↔「revealing subsurface landscape」，「summary」↔「provide a far more revealing picture」
答案：B
原文定位：Unless this process is clearly understood;the hard work now underway of planning and tree-planting on the surface may be rendered ineffective
同义替换：「current re-vegetation practices」↔「tree-planting on the surface」，「a waste of time」↔「rendered ineffective」，「possibility」↔「may」
答案：Can show the composition of the top layer of the ground.
原文定位：Electromagnetic surveys measure the electrical conductivity of soil to reveal the distribution of salt and the nature and variability of the regolith - the weathered rock and sediment that may lie above the bedrock
同义替换：「show the composition」↔「reveal the distribution of salt and the nature and variability」，「top layer of the ground」↔「regolith」
答案：Can help farmers choose the best location for plants.
原文定位：Radiometric analysis;help determine where to plant particular crop species to tackle the problem
同义替换：「help farmers choose the best location for plants」↔「determine where to plant particular crop species」
答案：Can detect how far below ground the salt is.
原文定位：Advanced airborne electromagnetics, in particular, enables scientists to take ‘slices’ of the landscape at depths of five metres, ten metres, fifteen metres and so on, to determine where salt may be stored at depth
同义替换：「detect how far below ground the salt is 」↔「determine where salt may be stored at depth」
答案：The same techniques can be used to find both.
原文定位：A suite of high technologies used by geologists to see underground and prospect for gold and minerals is now being used to pinpoint the presence of salt beneath the landscape
答案：salt's ability to travel below ground
原文定位：Unless this process is clearly understood;salt can still sneak past and erupt, following one of the ancient river channels formed millions of years ago
同义替换：「travel below ground」↔「sneak past」
答案：some possible measures may cause farmers to lose income
原文定位：How do you introduce the land-use changes that are needed when people still need to make a living
同义替换：「some possible measures」↔「land-use changes」，「cause farmers to lose income」↔「people still need to make a living」
答案：Farmers are fighting an enemy that moves secretly and hides well
原文定位：impassive surface of Australia lie hidden mountains, valleys and gorges - ancient traps and channels for the deadly salt that is stealthily killing so much of the Australian landscape;salt can still sneak past and erupt;salt's ability to mount ambushes, emerging somewhere new, sometimes unexpected and unexplained
同义替换：「moves secretly」↔「stealthily」，「hides well」↔「ambushes」