13.9土壤侵蚀
Section outline
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Could it happen again?
::会不会再发生一次?Farmers were forced off their lands during the Dust Bowl in the 1930s. The rains stopped, and the topsoil blew off these former grasslands. This scene was repeated throughout the central United States. During long droughts, some people wonder if another dust bowl could come.
::在1930年代的尘土碗期间,农民被迫离开自己的土地。 雨停了,表土从这些以前的草原上喷出。 这一场景在美国中部一再发生。 在长期干旱期间,有些人怀疑是否还会再出现一个灰缸。Causes of Soil Erosion
::土壤侵蚀原因The same agents that erode landscapes also erode soil . They are water , wind , ice, or gravity. Running water is the leading cause of soil erosion . Water is abundant and has a lot of power. Wind is also a leading cause of soil erosion. Wind can pick up soil and blow it far away.
::侵蚀地貌的同一种物剂也侵蚀土壤,它们是水、风、冰或重力。自来水是土壤侵蚀的主要原因。水是充沛的,并且具有很大的力量。风也是土壤侵蚀的一个主要原因。风可以把土壤拾起并吹到很远的地方。Activities that remove vegetation, disturb the ground, or allow the ground to dry are activities that increase erosion. What are some human activities that increase soil erosion?
::清除植被、扰动地面或使地面干燥的活动是增加侵蚀的活动。Farming
::农业农业The photos below ( Figure ) show how farming practices can increase soil erosion. Plant roots penetrate the soil and keep it from eroding. Plowing turns over bare soil and cuts through plant roots. Bare soil is exposed to wind and water. In the past, farmers always plowed fields before planting.
::以下照片(图)显示耕作做法如何会增加土壤侵蚀;植物根植于土壤中,防止土壤侵蚀;耕种将裸露的土壤翻倒,通过植物根切开;贫瘠的土壤暴露在风和水中;过去,农民在耕种前总是耕种田地。The problem doesn’t stop with plowing. Crops are usually planted in rows with bare soil in between the rows. In places where crops grow only during part of the year , the land may be bare for a few months.
::问题并不止于耕种。 作物通常种植在两排之间,排成一排,两排之间有裸露的土壤。 在作物只种植一年中一部分时间的地方,土地可能光露几个月。Farming leaves some soil exposed to erosion.
::农业使一些土壤受到侵蚀。The soil that is most likely to erode is the nutrient-rich topsoil. The loss of topsoil degrades the farmland.
::最有可能腐蚀的土壤是富营养的表土,表土的流失使农田退化。Grazing
::放牧As pictured below ( Figure ), some grazing animals, especially sheep and goats, eat grass right down to the roots. They may even pull the grass entirely out of the ground. Grazing animals can kill the grass. They may thin it out so much that it offers little protection to the soil. If animals are kept in the same place too long, the soil may become completely bare. The bare soil is easily eroded by wind and water.
::如下图(图)所示,一些放牧动物,特别是绵羊和山羊,从草根直到草根吃草,甚至可以把草完全从地上拔出来,放牧动物可以杀死草,将草稀释出来,对土壤几乎没有什么保护,如果将动物放在同一地方太久,土壤就可能完全裸露,裸露的土壤很容易被风和水侵蚀。Sheep and goats can damage plants and leave the soil bare.
::绵羊和山羊可以破坏植物,使土壤裸露。Logging, Mining, and Construction
::伐木、采矿和建筑Other human actions that put soil at risk include logging, mining, and construction. You can see examples of each below ( Figure ).
::使土壤处于危险的其他人类行为包括伐木、采矿和建筑。 您可以参看以下各例(图 )。- When forests are cut down, the soil is suddenly exposed to wind and rain . Without trees, there is no leaf litter to cover the ground and protect the soil. When leaf litter decays, it adds humus and nutrients to the soil.
::当森林被砍伐时,土壤突然暴露在风雨之下,没有树木,没有叶子覆盖地面和保护土壤。当叶子腐烂时,叶子会增加土质和养分。
- Mining and construction strip soil off the ground and leave the land bare.
::采矿和建筑将土壤从地面上剥去,使土地赤裸裸。
- Paved roads and parking lots prevent rainwater from soaking into the ground. This increases runoff and the potential for soil erosion.
::铺设的道路和停车场防止雨水渗入地面,这增加了径流和土壤侵蚀的可能性。
Logging, mining, construction, and paving surfaces are some of the ways that soil erosion increases.
::伐木、采矿、建筑和铺路面是土壤侵蚀加剧的一些方式。Recreation
::娱乐Even things that people do for fun can expose soil to erosion. For example, overuse of hiking trails can leave bare patches of soil. Off-road vehicles cause even more damage; examples of this are pictured below ( Figure ).
::即便人们为了玩乐而做的事情也有可能使土壤受到侵蚀。 比如,过度使用徒步足迹可以留下空空的土壤块。 越野车辆造成更大的破坏;这方面的例子见下文(图 ) 。What’s fun for people may be bad for soil. Off-road vehicles can destroy plants and leave the ground bare. This sets up the soil for erosion.
::对于人们来说,有趣的是土壤可能不好。 越野车辆可以摧毁植物,让地面赤裸裸。 这造成土壤侵蚀。Soil erosion is a natural occurrence. However, human activities have greatly accelerated soil erosion. In some locations, soil may now be eroding about 10 times faster than its natural rate. Since Europeans settled in the United States, approximately one-third of the topsoil has eroded away.
::土壤侵蚀是一种自然现象,然而,人类活动大大加速了土壤侵蚀。 在某些地方,土壤侵蚀速度可能比自然侵蚀速度快10倍左右。 自从欧洲人在美国定居以来,大约三分之一的表土已经消失。Summary
::摘要- Soil erosion is a natural process, but human activities can increase it.
::土壤侵蚀是一个自然过程,但人类活动可以增加土壤侵蚀。
- The main agents of soil erosion are water and wind.
::水和风是土壤侵蚀的主要诱因。
- Soil erosion is more likely where the ground has been disturbed. Farming, grazing animals, logging, mining, construction, and recreational activities can do this.
::土壤侵蚀在土壤被扰动的地方更有可能发生,农业、放牧动物、伐木、采矿、建筑和娱乐活动可以做到这一点。
Review
::回顾- What are the agents of soil erosion?
::什么是土壤侵蚀的诱因?
- How does farming accelerate soil erosion?
::耕作如何加速土壤侵蚀?
- How does grazing accelerate soil erosion?
::放牧如何加速土壤侵蚀?
- What is common about the human activities that increase soil erosion, such as logging, hiking, or driving an off-road vehicle?
::增加土壤侵蚀的人类活动,例如伐木、徒步旅行或驾驶越野车辆,有什么共同之处?
- What happens when the rate of soil erosion increases?
::当土壤侵蚀率上升时会怎样?
- Which layer of soil is usually lost?
::通常损失的土壤是哪一层?
Explore More
::探索更多Use the resource below to answer the questions that follow.
::利用以下资源回答以下问题。- Why was the steel plow important?
::为什么钢犁很重要?
- What was needed during World War I?
::第一次世界大战期间需要什么?
- Why was the soil of this region particularly vulnerable to erosion?
::为什么该地区的土壤特别容易受到侵蚀?
- What had occurred by 1929?
::1929年发生了什么?
- What happened in 1930? What was the problem with replacing prairie grasses with crops?
::1930年发生了什么?用作物取代草原草有什么问题?
- What was a black blizzard?
::什么是黑色暴风雪?
- How could the Dust Bowl have been prevented?
::怎样才能阻止尘土碗呢?
- How has this region survived more recent droughts? Think about other sections you've studied, what might another reason be?
::想想你研究过的其他部分,还有别的原因吗?
- When forests are cut down, the soil is suddenly exposed to wind and rain . Without trees, there is no leaf litter to cover the ground and protect the soil. When leaf litter decays, it adds humus and nutrients to the soil.
