Read and translate the text with the help of a dictionary. Soils considered as a natural body by Russian and US scientists in the late 1800s. Parent material Soils are formed by weathering of “parent materials”

Soils considered as a natural body by Russian and US scientists in the late 1800s. This allowed scientists to study and classify soils with the objective of trying to understand soil formation from an environmental perspective. They recognized that soils were formed by weathering of surface deposits or “parent materials” by processes that were physical, chemical and biological. The concept of soil forming factors allows scientists to understand and classify soils more clearly.

Parent material Soils are formed by weathering of “parent materials”. These materials have many origins such as bedrock surfaces, aolian (wind blown), lacustrine (from glacial lake beds), alluvium (river) and organic (peat) deposits.

Many of our soils have been developing since the last ice age – some 10 thousand years ago. Soil is in a dynamic equilibrium. It is always changing as a result of its interaction with the environment.

Glaciation The most important parent materials come from glaciers which retreated from the prairies about 10, 000 years ago. The glaciers, often several thousand feet high, had the power to move rocks and debris from the north carrying them hundreds of miles and depositing them all over the province as the ice melted.

Only small areas escaped glaciation. There is evidence of early settlement of people in the prairies immediately following glaciation some 10, 000 years ago (possibly part of a group of migrants from Asia who walked across the frozen Baring Sea and moved south to populate the Americas).

Physical weathering The conversion of large rock matter into small (mineral) particles is mainly the result of physical weathering. Glacial erosion, wind and water are the major physical forces involved in this type of weathering. While erosion can be witnessed day to day, like the movement of water over surfaces or a blowing wind that picks-up and deposits particles, the formation of soils by this type of weathering took many, many years. The action of freezing water (and expanding in rock cracks or fissures), gravity movements (earthquakes and landslides), the burrowing actions by organisms or the movement animals across the land, are also physical forces.

Chemical weathering Processes which break down rock matter to produce smaller, chemically different substances are included in this category. Examples of chemical weathering include

1. the reaction of iron and oxygen to form iron oxide (rust)

2. dissolving of limestone (a base) in water which contains carbon dioxide, making the water slightly acidic.

Biological actions Biological action begins the process of weathering at the very early stages as lichens and mosses desperately cling to the barren surfaces of rocks. They open up fissures and scrounge nutrients where they can, producing acids and chelating agents in an attempt to dissolve nutrients from the hostile environment. As the soil develops further the microfauna and microflora play their part in the development of humus. Billions of tiny plants and animal live, reproduce, grow and die in the soil, constantly adding organic matter to its composition.

The soil is a habitat for living things that carry out the biological actions. These living organisms in the soil provide

1. a cover of vegetation to protect the soil.

2. nutrients (through decomposition, there is an addition of organic matter).

3. roots to help bind soil particles.

4. mixing of soil components ( by the action of animal organisms such as ants, worms)

5. cycling of nutrients.

All of the organisms that live in the soil have a place in the soil ecosystem. The next time you decide to step on an ant or dig up that earthworm, consider how these animals benefit the soil society.

2.5 Give English equivalents: почвообразующие факторы, ледниковый период, возвышенности, динамическое равновесие, катастрофические последствия, глинистая почва, каменистая почва, огромные ледниковые озера, по направлению к западу, землетрясение, ржавчина, слегка кислый, миллиарды мелких растений, лупа, разложение.

Text 3

Soil Classification

3.1 Read the following international words and translate them: classification, production, taxonomy, facts, systems, scheme, reason, characteristics, groups, erosion, profile, horizon, chemical, basis, deficiency.

3.2 Say it in Russian: Russian scientist, soil’s morphology, Canadian system, soil profile characteristics, other similar areas, flooding, wind erosion, soil horizons, texture and structure.

⇐ Предыдущая12345678910Следующая ⇒

Поделиться: