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  • 土壤和水

    What you will learn 
    ::你会学到什么

    • Soil and water resources and their misuse by humans
      ::土壤和水资源以及人类对土壤和水资源的滥用
    • How runoff causes algal blooms and creates dead zones in bodies
      ::径流如何导致藻类开花,如何在身体中造成死亡地带

    lesson content

    Could this land be used for agriculture?
    ::这块土地能否用于农业?

    Probably not. The quality of soil is very important in determining what can grow in a particular area. Good soil is not so easy to come by. Soil should be considered another resource that we, as a , must strive to protect.
    ::土壤质量对于确定在特定地区可以种植什么非常重要,良好的土壤并非易得。 土壤应被视为我们作为一个国家必须努力保护的另一种资源。

    Soil and Water Resources
    ::土壤资源及土壤水资源

    Theoretically, soil and water are . However, they may be ruined by careless human actions.
    ::理论上说,土壤和水是,然而,它们可能因人类粗心大意的行为而被毁坏。

    Soil
    ::土壤土壤土壤

    Soil is a mixture of eroded rock, minerals , partly decomposed organic matter, and other materials. It is essential for , so it is the foundation of . Soil is important for other reasons as well. For example, it removes toxins from water and breaks down wastes.
    ::土壤是被侵蚀的岩石、矿物、部分分解的有机物和其他材料的混合体。土壤对于......至关重要,因此它是......的基础。由于其他原因,土壤也很重要。例如,土壤将毒素从水中清除出来,并粉碎废物。

    Although renewable, soil takes a very long time to form—up to hundreds of millions of years. So, for human purposes, soil is a . It is also constantly depleted of nutrients through careless use, and eroded by wind and water. For example, misuse of soil caused a huge amount of it to simply blow away in the 1930s during the Dust Bowl (see Figure  ). Soil must be used wisely to preserve it for the future. practices include contour plowing and terracing. Both reduce soil erosion. Soil also must be protected from toxic wastes.
    ::土壤虽然可再生,但需要很长的时间才能形成——高达数亿年。因此,就人类而言,土壤是一种土壤。土壤也由于不小心使用而不断耗竭养分,并受到风和水的侵蚀,例如,土壤的滥用导致土壤大量在1930年代尘土碗期间被吹走(见图 ) 。土壤必须明智地用于保护未来。 做法包括轮廓耕种和梯田。两者都减少了土壤侵蚀。土壤也必须受到保护,免受有毒废物的污染。

    Images of the Dust Bowl
    The Dust Bowl occurred between 1933 and 1939 in Oklahoma and other southwestern U.S. states. Plowing had exposed prairie soil. Drought turned the soil to dust. Intense dust storms blew away vast quantities of the soil. Much of the soil blew all the way to the Atlantic Ocean.

    Water
    ::水 水

    Water is essential for all life on Earth. For human use, water must be fresh. Of all the water on Earth, only 1 percent is fresh, liquid water. Most of the rest is either salt water in the ocean or ice in glaciers and ice caps.
    ::水是地球上所有生命所必不可少的。对于人类来说,水必须是淡水。地球上的所有水中,只有1%是淡水和液态水,其余大部分是海水中的盐水或冰川和冰盖中的冰。

    Although water is constantly recycled through the , it is in danger. Over-use and pollution of freshwater threaten the limited supply that people depend on. Already, more than 1 billion people worldwide do not have adequate freshwater. With the rapidly growing , the water shortage is likely to get worse.
    ::淡水的过度使用和污染威胁着人们赖以生存的有限供应。 全世界已有10亿多人没有充足的淡水。 随着水的迅速增长,缺水可能更加严重。

     

     

    Too Much of a Good Thing
    ::太多好东西了

    comes from many sources. One of the biggest sources is runoff. Runoff picks up chemicals such as fertilizer from agricultural fields, lawns, and golf courses. It carries the chemicals to bodies of water. The added nutrients from fertilizer often cause excessive growth of , creating algal blooms (see Figure  ). The up oxygen in the water so that other aquatic organisms cannot survive. This has occurred over large areas of the ocean, creating dead zones , where low oxygen levels have killed all ocean life. A very large dead zone exists in the Gulf of Mexico. Measures that can help prevent these problems include cutting down on fertilizer use. Preserving wetlands also helps because wetlands filter runoff water.
    ::最大的来源之一是径流。 径流从农田、 草坪和高尔夫球场中收集了化肥等化学物质。 径流从农田、 草坪和高尔夫球场中收集了化肥等化学物质。 它把化学物质带到水体中。 化肥中添加的养分往往导致过度生长, 造成藻类开花(见图 ) 。 水中的氧气增加, 使得其他水生生物无法生存。 这发生在大片海洋地区, 造成了死区, 低氧水平导致所有海洋生物死亡。 墨西哥湾存在一个非常大的死区。 有助于防止这些问题的措施包括减少肥料的使用。 保护湿地也因为湿地过滤径流水而有所帮助。

    Nutrients in fertilizer cause an algal bloom
    Algal Bloom. Nutrients from fertilizer in runoff caused this algal bloom.

    Summary
    ::摘要

    • Soil and water are renewable resources but may be ruined by careless human actions. Soil can be depleted of nutrients. It can also be eroded by wind or water.
      ::土壤和水是可再生资源,但可能因人类的粗心行为而毁坏,土壤可能耗竭养分,也可能被风或水侵蚀。
    • Over-use and pollution of freshwater threaten the limited supply that people depend on.
      ::淡水的过度使用和污染威胁到人们赖以生存的有限供应。

    Review
    ::回顾

    1. What is soil?
      ::什么是土壤?
    2. Why is soil considered a nonrenewable resource?
      ::为什么土壤被视为不可再生资源?
    3. How much water is drinkable?
      ::有多少水可以饮用?
    4. Why would you expect a dead zone to start near the mouth of a river, where the river flows into a body of water?
      ::为什么你会期望一个死区 开始在河口附近? 河水流进水中?