Tag: evs

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Multiple choice evs mud and stones importance of soil in agriculture soil - formation, profile and properties soil as a natural resource

Choose the correct answer from the alternatives given.
The fertility of soil is reduced by

  1. ammonifying bacteria

  2. denitrifying bacteria

  3. nitrifying bacteria

  4. nitrogen fixing bacteria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Decomposers also break down the bodies of dead organisms resulting in nitrogen being returned to the soil as ammonia. In some conditions, denitrifying bacteria in the soil break down nitrates and return nitrogen to the air. This is usually in waterlogged soil. Hence, making it unavailable for plant roots. So, the correct option is 'Denitrifying bacteria'

Multiple choice evs mud and stones importance of soil in agriculture soil - formation, profile and properties soil as a natural resource

Models of vegetables are made with this soil :

  1. Sandy

  2. Sticky

  3. Rocky

  4. All the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sticky soil, which contains a high proportion of clay, is pliable and retains its shape well, making it ideal for molding models of vegetables. Other soil types lack the necessary cohesion and plasticity for fine modeling work.

Multiple choice evs mud and stones importance of soil in agriculture soil - formation, profile and properties soil as a natural resource

Which one is the main source of minerals essential for man and other organisms?

  1. Lithosphere

  2. Ionosphere

  3. Mesosphere

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

The lithosphere serves as a source of minerals. The minerals supply the basic materials, required for making a variety of commodities, which man uses daily. The lithosphere is also the major source of fuels, such as coal, petroleum and a natural gas. 

The lithosphere in combination with the hydrosphere and the atmosphere plays a vital role in the growth of plants and animals. It provides nutrients to the plants. The plants are the source of food for man and all other animals.

Multiple choice evs mud and stones importance of soil in agriculture soil - formation, profile and properties soil as a natural resource

Materials of biological origin which are commonly used to maintain and improve soil fertility are 

  1. green manures

  2. biofertilizers

  3. bioinsecticides

  4. both (a) and (b).
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Green manures are added to the soil to increase the productivity. Manures is of natural origin. The presence of nutrients in manure have a great role in increasing soil fertility. Biofertilizers are organisms which enrich the soil with nutrients e.g., Rhizobiumin symbiotic association with legume plants.

Multiple choice evs mud and stones importance of soil in agriculture soil - formation, profile and properties soil as a natural resource

When large patches of forests are being cleared for cultivation of crops, the environmental impact of such a practice would lead to______

  1. Soil erosion

  2. Soil conservation

  3. Soil pollution

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

 Deforestation is a direct cause of the erosion happening in tropical rain forests. Once plant cover is gone there are no roots to hold the soil in place during heavy tropical rains, which then wash away the topsoil and the nutrients necessary to regenerate future vegetation.