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IV. What chemical conditions of soil do you know?

 

TEXT 8 HOW SOILS ARE CLASSIFIED

Pedologists classify soils according to the characteristics of a polypedon. The Soil Survey Staff of the United States Department of Agriculture uses a system that consists of 10 orders (groups) of soils. They are alfisols, aridisols, entisols, histosols, inceptisosl, mollisols, oxisols, spodosols, ultisols, and vertisols.

Alfisols develop under forest and grasslands in humid climates. Some agricultural soils are alfisols.

Aridosols occur in dry regions and contain small amounts of organic matter. Desert soils are ardisols.

Entisols show little development. They resemble the parent material and occur in many climates.

Histosols are organic soils. They form in water saturated environments, including swamps and bogs.

Inceptisols are only slightly developed. They are more common in subhumid and humid climates, but also occur in most other kinds of climates.

Mollisols develop in prairie regions. They have thick, organically rich topsoils.

Oxisols are the most chemically weathered soils. They have a reddish color and occur in tropical regions.

Spodosols contain iron, aluminum, and organic matter in their B horizons. They form in humid climates.

Ultisols occur in warm, humid climates. They are moist, well-developed, acid soils.

Vertisols form in subhumid and arid warm climates. They develop wide, deep cracks during dry seasons.

 

I. Study the following words:

 

Polypedon, staff, agriculture, consist, alfisols, aridisols, entisols, histosols, inceptisols, mollisols, oxisols, spodosols, ultisols, vertisols, humid, grassland, occur, swamp, bog, reddish, moist, crack.

 

II. Complete the sentences with appropriate words from the text and translate them into your language:

1. … occur in warm, humid climates .

2. Oxisols are the most … weathered soils.

3. They … the parent material and occur in many climates.

4. They have a … color and … in tropical regions.

5. They are …, well-developed, acid soils.

 

III . Say true or false these statements are, correct false ones:

There are nine orders (groups) of soils.

Aridisols resemble the parent material and occur in many climates.

Entisols are organic soils.

Oxisols are the most chemically weathered soils.

Histosols form in water-saturated environments, including lakes and bogs.

Spodosols contain iron, aluminum, and organic matter in their B horizons.

 

IV. Give the characteristics of all soil classifications.

 

TEXT 9 SOIL CONSERVATION

The soils of farmlands, grazing lands, and forestlands provide many products and recreational areas. Soil conservationists work to ensure the wise use of these soils.

Wise use of farmlands involves maintaining a high level of nutrients and organic matter in cultivated soils. Farmers add organic matter to the soil by plowing under certain green plants. They also add fertilizers and rotate crops to replace nutrients that leaching and growing plants remove. In addition, farmers plow and plant their fields in ways that control erosion.

Grazing lands that have been overgrazed also suffer from erosion. Overgrazing decreases the amounts of plant life and organic matter in the soil, and the soil erodes easily. Ranches conserve grazing lands by limiting the time that their herds graze in one area.

Forestlands also must be protected from erosion. In some cases, foresters leave unusable branches and other parts of trees on the forest floor to add organic matter to the soil. They also develop large groups of trees whose roots protect the soil by holding it in place against wind and water erosion.

 

I. Study the following words:

Farmlands, grazing lands, recreational areas, ensure, wise, involve, cultivated soils, fertilizers, remove, suffer, wind erosion.

 

II. Make up your own sentences with the following word combinations:

Grazing lands, wise use, soil conservation, unusable branch, organicmatter.

 

III. Translate the following sentences into your language:

1. Wise use of farmlands involves maintaining a high level of nutrients and organic matter in cultivated soils.

2. Overgrazing decreases the amounts of plant life and organic matter in the soil, and the soil erodes easily.

3. Farmers add organic matter to the soil by plowing under certain green plants.

4. They also develop large groups of trees whose roots protect the soil by holding it in place against wind and water erosion.

5. Ranchers conserve grazing lands by limiting that their herds graze in one area.

 

IV. Retell the text ‘ Soil conservation.’

Последнее изменение этой страницы: 2016-08-29

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