Tag: evs

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Questions Related to evs

Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Build up of organic material in soil is under which of the following conditions to

  1. $< 10^oC$ temperature, Absence of oxygen.

  2. Warm temperature, Humid environment
  3. Aerobic conditions, $>25^oC$ temperature

  4. Nitrogen rich detritus, optimum moisture
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Presence of oxygen is necessary for the growth of a microorganism in the organic matter. Under anaerobic conditions most of fungi and actinomycetes growth suppressed only a few bacteria grow in anaerobic organic decomposition. The rate of temperature for maximum growth of the microorganism is 30° to 40°'. The adequate moisture is required for the proper decomposition of organic matter. The rate of decomposition of organic matter is maximum in the neutral soils than the acidic soil. C: N  ratio has a great influence on the decomposition. Narrow C: N ratio of soil and organic water is required for rapid and better decomposition of organic matter.

So, the correct answer is ' Aerobic conditions, > 25°C temperature '


Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Which is the characteristic feature of a physiologically dry soil? 

  1. There is plenty of water in the soil

  2. Light available to the plants is not sufficient

  3. Concentration of salts is very high in soil water

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Physiologically dry soil have very high concentration of salts. It is basicly dead soil from lack of oxygen and high salt content. The halophytes are plants of physically wet but physiologically dry habitats. Such plants are commonly found near sea-shores where mesophytes and freshwater hydrophytes cannot thrive well. Although these plants grow in the areas which are well saturated with water yet they cannot avail of the water because of high concentration of salts in the soils. 

Therefore, the correct answer is option C. 

Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Mole drainage is practised extensively in country

  1. New Zealand

  2. Japan

  3. U.S.A.

  4. China
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mole drainage is widely used in New Zealand and the United Kingdom in heavy soils to improve productivity of pastures and crops. Mole drains are used in heavy soils where a clay subsoil near moling depth (400 to 600 cm) prevents downward movement of ground water. The aim of mole drainage is to fracture and crack the soil in order to improve the capacity of the soil to transmit water. Mole drainage is used in impermeable soils as a cost-effective means of facilitating a shallow pipe drain network. Mole drainage is suited to soils with a high clay content which form stable channels.

Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Water logged soil is

  1. Physically as well as physiologically dry

  2. Physically wet but physiologically dry

  3. Physically dry

  4. Physically as well as physiologically wet
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A soil may be physically wet; but if the plants absorb the water only with difficulty, as in a salty marsh water logged soil, then the soil is physiologically dry. The halophytes are plants of physically wet but physiologically dry habitats. Such plants are commonly found near sea-shores where mesophytes and freshwater hydrophytes cannot thrive well. Although these plants grow in the areas which are well saturated with water yet they cannot avail of the water because of high concentration of salts in the soils. 

Therefore, the correct answer is option B. 

Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Which of the following is not an example of a soil conservation practice?

  1. Contour farming

  2. Terracing

  3. Strip farming

  4. Planting wind breaks

  5. All of the above are examples of soil conservation practices
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Explanation: Soil conservation is the prevention of soil from erosion or reduced fertility caused by overuse, acidification, salinization or other chemical soil contamination. Slash-and-burn and other unsustainable methods of subsistence farming are also practiced in some lesser developed areas.

Multiple choice evs mud and stones soil types types of soil soil - types, uses and need for conservation

Plants growing on sandy soil are

  1. Lithophytes

  2. Psammophytes

  3. Hydrophytes

  4. Xerophytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Psammophytes are plants that thrive in shifting sands, primarily in deserts. They have a number of adaptations that enable them to exist on wind-blown sands. 
  • Lithophytes are plants that grow on stones and rocks or in their crevices.
  • Hydrophytes are aquatic plants that live in water and are evolutionarily suited to thrive in aquatic environments.
  • Xerophytes are plant species that have adapted to live in dry or desert conditions. They have evolved to bear and survive in extreme and harsh environments.