6.0防止侵蚀
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Wind and water can change the shape of the land.
::风和水可以改变陆地的形状。
What do you know about the soil beneath your feet? Almost all living things depend on soil. The soil is where we grow our food. Did you know it is in danger?
::你对你脚下的土地了解多少？几乎所有的生物都依赖土壤。土壤是我们种植食物的地方。你知道它有危险吗？
Every year farmers lose many tons of soil from their fields. The soil is very important for them to grow their crops. Without good crops, we will have less food. How can we prevent soil loss?
::每年农民从田地里流失许多吨土壤。土壤对他们种植庄稼很重要。没有好庄稼，我们的食物就会减少。我们如何防止土壤流失？
Soil is lost in two ways. Water can erode, or move, the soil when it rains. The wind can pick up loose and dry soil and carry it away. Water and wind are like thieves when it comes to soil. They both can carry it away.
::土壤以两种方式流失。下雨时，水会侵蚀或移动土壤。风可以把松散干燥的土壤吹走。水和风在土壤上就像小偷。他们俩都能把它带走。
The Mississippi Delta was formed from stolen soil. It was once soil in the Midwest US. The Mississippi River carried this soil to where it is now. Wind and water play a major role in erosion. We know that soil is gained and lost from areas. We know it needs to be protected. Scientists want to learn about ways to prevent erosion.
::密西西比河三角洲是由偷来的土壤形成的。它曾经是美国中西部的土壤。密西西比河把这些土壤带到了现在的位置。风和水在侵蚀中起主要作用。我们知道，一个地区的土壤有得也有失。我们知道它需要保护。科学家们想要了解防止侵蚀的方法。
Scientists study rivers to learn about erosion. They also want to find ways to prevent it. They have built special structures. Some of these structures are in the river. They capture some of the stolen soil. Others are on the banks of the river. These prevent more erosion.
::科学家研究河流是为了了解侵蚀情况。他们也想找到预防的方法。他们建造了特殊的建筑。其中一些建筑在河中。他们捕获了一些偷来的土壤。其他的在河岸上。这些可以防止更多的侵蚀。
Wind too can steal soil from other areas. Some areas benefit from this new soil. The red soils of Bermuda were stolen by the wind. They were once the soil of Africa. The fertile soils of Illinois were brought in on the wind. They blew up from the Mississippi River valley after the last ice age.
::风也可以从其他地方偷走土壤。一些地区受益于这种新土壤。百慕大的红土被风偷走了。它们曾经是非洲的土壤。伊利诺斯州肥沃的土壤是由风带来的。它们在最后一个冰河时代之后从密西西比河流域爆炸而来。
For a farmer, losing soil is not good. Farmers can lose their thick rich topsoil. What is left is less fertile ground not suited for growing crops. This is why we must be careful. Scientists study soil loss and work on ways to prevent it. Can you think of some ways?
::对农民来说，失土是不好的。农民会失去厚厚的肥沃的表土。剩下的是不太肥沃的土地，不适合种植作物。这就是我们必须小心的原因。科学家们研究土壤流失，并研究防止土壤流失的方法。你能想到一些办法吗？
Soil needs plants to protect it. Plants' roots help hold it in place. Farmers now leave some vegetation in their fields. They do not want to lose their fertile soil. Planting trees along fields can block the wind. By slowing the wind, it prevents the soil from blowing away. How can we protect the soil from water erosion?
::土壤需要植物来保护。植物的根帮助它固定在适当的位置。农民们现在在田地里留下一些植被。他们不想失去肥沃的土壤。沿着田地种树可以挡风。通过减缓风的速度，它可以防止土壤被吹走。我们如何保护土壤不受水分侵蚀？
Plants also protect soil from water erosion. The plants help the soil stay in place. They protect the soil from the impact of rain. Steep slopes increase water erosion. Some farmers use special techniques to keep their fields level. Level fields are in much less danger from erosion.
::植物还能保护土壤免受水分侵蚀。植物帮助土壤保持原位。它们保护土壤不受雨水的影响。陡坡加剧了水土流失。一些农民使用特殊的技术来保持田地的平整。平地受到侵蚀的危险要小得多。
What are some ways you can prevent erosion at your home?
::有哪些方法可以防止家里的腐蚀呢？
