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  • 土壤层位和剖面

    Lesson
    ::经验教训

     

    Soil profile showing distinct horizons beneath asphalt, indicating different soil layers.

     

    What's beneath your car tires?
    ::你的车胎下面是什么?

    Beneath an asphalt road is this incredible  soil profile . Can you identify the horizons? There are some clues in the photo that can help you identify the  climate  type. What type of climate would produce this  soil ?
    ::在沥青路下方的沥青路是令人难以置信的土壤图。 您能辨别地平线吗 ? 照片中有些线索可以帮助您辨别气候类型 。 什么样的气候会产生这种土壤?

    Soil Horizons and Profiles
    ::土壤地平线和概况

    Soil develops over time and forms soil horizons.  Soil horizons  are different layers of soil with depth. The most  weathering  occurs in the top layer. This layer is most exposed to weather! It is where fresh  water  comes into contact with the soil. Each layer lower is weathered just a little bit less than the layer above. As water moves down through the layers, it is able to do less work to change the soil. This is because the chemical reactions have already occurred.
    ::土壤随时间和形态形成土壤地平线。 土壤地平线是具有深度的不同土壤层。 最风化的是在顶层。 最受气候影响的是顶层。 这个层最受气候影响。 淡水与土壤接触的地方就是这个层。 下层每层的天气都比上层少一点。 当水从层向下移动时, 它能够减少改变土壤的工作。 这是因为化学反应已经发生 。

    If you dig a deep hole in the ground, you may see each of the different layers of soil. All together, the layers are a  soil profile . Each horizon has its own set of characteristics ( Figure   ). In the simplest soil profile, a soil has three horizons.
    ::如果您在地面上挖一个深洞, 你就可以看到土壤的不同层。 这些层加起来就是一个土壤剖析图。 每个地平线都有自己的特征( 图 ) 。 在最简单的土壤剖析图中, 土壤有三个地平线 。

    Soil horizons with labeled layers and grass on top.

     

    In this diagram, a cut through soil shows different soil layers.
    ::在本图中,通过土壤的切口显示了不同的土壤层。

    Topsoil
    ::上表土土

    The first horizon is the “A“ horizon. It is more commonly called the  topsoil . The topsoil is usually the darkest layer of the soil. It is the layer with the most  organic  material.  Humus  forms from all the plant and animal debris that falls to or grows on the ground. The topsoil is also the region with the most biological activity. Many organisms live within this layer. Plant roots stretch down into this layer. The roots help to hold the topsoil in place. Topsoil is needed to grow most crops ( Figure   ).
    ::第一个地平线是“A”地平线,通常称为表土。表土通常是土壤中最黑暗的一层。表土通常是土壤中最黑暗的层。表土是具有最有机材料的层。来自落地或生长在地面上的所有植物和动物碎片的Humus形态。表土也是生物活动最多的地区。许多生物都生活在这一层中。植物根植于这一层中。植物根植于这一层中。根植有助于将表土固定在原地。需要表土来种植大多数作物(图示 )。

    A farm field with rows of plants and supports in the background.

     

    Good topsoil is great for growing plants.
    ::良好的表土对植物生长很有帮助

    Topsoil usually does not have very small particles like clay. Clay-sized particles are carried to lower layers as water seeps down into the ground. Many   dissolve in the fresh water that moves through the topsoil. These minerals are carried down to the lower layers of soil.
    ::灰土通常没有像粘土这样的非常小的微粒。 当水渗入地表时, 克莱大小的微粒会携带到下层。 许多微粒会溶解在穿过表层土的淡水中。 这些矿物会传到下层的土壤中 。

    Subsoil
    ::底土 底土

    Below the topsoil is the “B“ horizon. This is also called the  subsoil . Soluble minerals and clays accumulate in the subsoil. Because it has less organic material, this layer is lighter brown in color than topsoil. It also holds more water due to the presence of iron and clay. There is less organic material in this layer.
    ::在表层土下是“B”地平线,它也称为底土,可溶性矿物和粘土在底土中积累,由于有机物质较少,这个层的颜色比表层土浅,由于铁和粘土的存在,它也拥有更多的水,这个层的有机物质较少。

    C-horizon
    ::C- 等离子( C)

    The next layer down is the “C” horizon. The  C horizon  is made of partially altered bedrock. There is evidence of weathering in this layer. Still, it is possible to identify the original   type from which this soil formed ( Figure   ).
    ::下一层是“ C” 地平线。 C 地平线由部分改变的基岩组成。 有证据表明该层有气候变迁的迹象。 尽管如此,还是可以确定土壤的原始类型( 图 ) 。

    Soil horizons: O, A, B, C layers, and parent material with water infiltration.

     

    This image shows the various soil horizons.
    ::此图像显示各种土壤地平线 。

    Not all climate regions develop soils. Arid regions are poor at soil development. Not all regions develop the same soil horizons. Some areas develop as many as five or six distinct layers. Others develop only a few.
    ::并非所有气候区域都发展土壤,干旱区域在土壤开发方面贫乏,并非所有区域都发展同样的土壤地平线,有些区域发展到5或6个不同的层,另一些区域发展到很少的层。

    Summary
    ::摘要

    • Soil horizons are layers within a soil. Different soil horizons show different amounts of alteration.
      ::土壤地平线是土壤中的多层,不同的土壤地平线显示有不同程度的改变。
    • Soil profiles reveal the different layers of soil.
      ::土壤概况显示不同层次的土壤。
    • Soil layers include topsoil, subsoil, and the C horizon.
      ::土壤层包括表土、底土和C地平线。
    • Topsoil has the highest proportion of organic material. Topsoil is essential for farming.
      ::表土在有机材料中的比例最高,对耕作来说,表土是必不可少的。

    Review
    ::回顾

    1. What is topsoil? Why is topsoil so important for growing plants?
      ::什么是表土?为什么表土对植物生长如此重要?
    1. How does weathering produce soil?
      ::天气如何产生土壤?
    1. Why does the C horizon most resemble the parent material?
      ::为什么C地平线最像母物质?

    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。

    1. What are the two main components of the A horizon and what is different about them?
      ::" A " 地平线的两个主要组成部分是什么,它们有什么不同?
    1. What is in the O-horizon? What is its more common name?
      ::O-ho-horizon是什么?它更常用的名称是什么?
    1. What distinguishes the E-horizon from the horizons above and below?
      ::E-horizon与上面和下面的地平线有何区别?
    1. In what regions do soils have an E-horizon?
      ::土壤在哪些区域有E-phorizon ?
    1. What are the characteristics of the B-horizon?
      ::B-horizon的特征是什么?
    1. How does the C-horizon differ from the other horizons?
      ::C-horizon与其他地平线有何不同?
    1. What is below the C-horizon?
      ::C -horizon下面是什么?