Tag: soil - formation and profile

Questions Related to soil - formation and profile

Soil building begins with the physical fragmentation of

  1. Lichens

  2. Humus

  3. Aggregate

  4. Parent material


Correct Option: D
Explanation:
The development of a soil would begin with the weathering of lava flow bedrock, which would produce the purely mineral-based parent material from which the soil texture forms. Soil development would proceed most rapidly from bare rock of recent flows in a warm climate, under heavy and frequent rainfall. This The mineral material from which a soil forms is called parent material. Rock, whether its origin is igneous, sedimentary, or metamorphic, is the source of all soil mineral materials and the origin of all plant nutrients with the exceptions of nitrogen, hydrogen and carbon. As the parent material is chemically and physically weathered, transported, deposited and precipitated, it is transformed into a soil.
So, the correct answer is 'Parent material'.

The dead rotting matter which is found in the water floating on the top layer belongs to 

  1. Matter

  2. Clay

  3. Humus

  4. Sand


Correct Option: C

The study of the vertical section of the layers of the soil is known as 

  1. Soil study

  2. Soil profile

  3. Soil layering

  4. Soil weathering


Correct Option: B
Explanation:
A soil profile consists of multiple horizontal layers of soil called horizons. Horizons occur parallel to each other. Each horizon is distinct from the other with respect to age, texture, color etc, these horizons can be observed when the soil layers are dug through vertically
So, the correct answer is 'Soil profile'

Weathering is the process of

  1. Formation of rock

  2. Formation of soil

  3. Formation of humus

  4. All of the above


Correct Option: B

The layer of humus in the soil profile is observed at

  1. The lowermost layer of the soil

  2. The topmost layer of the soil

  3. The soil layer beneath the clay

  4. The soil layer above the sand


Correct Option: B

The soil layer is made up of :

  1. R Horizon

  2. A Horizon

  3. B Horizon

  4. C Horizon


Correct Option: A
Explanation:

The soil layer is made up of R Horizon It is only between $5$ to $10$ inches thick and consists of organic matter and minerals. This layer is also called subsoil.

Soil profile means ______.

  1. Composition of the soil

  2. Texture of the soil

  3. Layers of the soil

  4. None of the above


Correct Option: C
Explanation:

A vertical section through different layers of the soil is called the soil profile.

So, the correct answer is 'Layers of the soil'

The weathering of rocks is caused by 

  1. Wind, water and climate

  2. Only wind and clay

  3. Only wind and water

  4. Wind, water and gravel


Correct Option: A

The weathering of rocks is caused by 

  1. Wind, water, and climate

  2. Only wind, and clay

  3. Only wind, and water

  4. Wind, water, and gravel


Correct Option: A

Soil has five components. The proportions of different components are

  1. Mineral Matter-$40\%$, Organic Matter-$10\%$, Soil Moisture -$25\%$, Soil Atmosphere -$25\%$, Soil Organism- Variable

  2. Mineral Matter-$40\%$, Organic Matter-$10\%$, Soil Moisture -$25\%$, Soil Atmosphere - $25\%$, Soil Organism- $10\%$

  3. Mineral Matter-$40\%$, Organic Matter-$10\%$, Soil Moisture -$35\%$, Soil Atmosphere -$25\%$, Soil Organism- $10\%$

  4. Mineral Matter-$30\%$, Organic Matter-$20\%$, Soil Moisture -$25\%$, Soil Atmosphere -$25\%$, Soil Organism- $10\%$


Correct Option: A
Explanation:

While a nearly infinite variety of substances may be found in soils, they are categorized into four basic components: minerals, organic matter, air and water. Most introductory soil textbooks describe the ideal soil (ideal for the growth of most plants) as being composed of 45% minerals, 25% water, 25% air, and 5% organic matter. In reality, these percentages of the four components vary tremendously. Soil air and water are found in the pore spaces between the solid soil particles. The ratio of air-filled pore space to water-filled pore space often changes seasonally, weekly, and even daily, depending on water additions through precipitation, throughflow, groundwater discharge, and flooding. The volume of the pore space itself can be altered, one way or the other, by several processes. Organic matter content is usually much lower than 5% . Some wetland soils, however, have considerably more organic matter in them (greater than 50% of the solid portion of the soil in some cases).


Microorganisms are the final basic element of soils, and they are found in the soil in very high numbers but make up much less than 1% of the soil volume. A common estimate is that one thimble full of topsoil may hold more than 20,000 microbial organisms. The largest of the these organisms are earthworms and nematodes and the smallest are bacteria, actinomycetes, algae, and fungi. Microorganisms are the primary decomposers of raw organic matter. Decomposers consume organic matter, water, and air to recycle raw organic matter into humus, which is rich in readily available plant nutrients.

So the correct option is 'Mineral Matter-40%,Organic Matter-10%,Soil Moisture -25%, Soil Atmosphere -$25$%,Soil Organism- Variable'.