Environmental Studies · Geography

Soil Science

1,499 Questions

Soil Science examines the formation, classification, and properties of soil as a critical natural resource. This hub offers practice questions covering soil horizons, soil types like laterite and black soil, and regional soil characteristics. The content is highly useful for agriculture exams and civil services preparation.

Soil typesSoil horizonsSoil formation factorsAgricultural soil requirementsIndian soilsForest and mountain soils

Soil Science Questions

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Soil hold water in it, it is called as 

  1. Soil water

  2. Ground water

  3. Soil moisture

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

Soil water is often referred to as soil moisture. Soil is the amount of water present in the interparticle spaces in the soil and is available to plants. When soil moisture gets depleted, enough water is not available for plants. So they have to apply more pressure in obtaining water from around the soil particles. 

So, option C "Soil Moisture" is the correct option.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Which is the characteristic featue of a physiologically dry soil ?

  1. Light available to plants is not sufficient

  2. There is plenty of water in the soil

  3. Concentration of salts is very high in the soil

  4. Soil is stony
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A physiologically dry soil is a soil in which the concentration of oxygen is very less and that of salt is very high. Normal plants cannot grow in such soil and only halophytes are found in them. The Sunderbans in West Bengal are rich in physiologically dry soil. Thus the correct answer is option C.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Soil that is rich in soluble salts is

  1. Laterite

  2. Halomorphic

  3. Calcimorphic

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the steppes and deserts, evaporation greatly exceeds precipitation. The products of rock weathering are brought by intermittent flowing streams during a flood and left behind on the basin floor. This soil has clay, silt and sand are the dissolved mineral salts and is called halomorphic soil. Thus the correct answer is option B. 

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

The top soil is darker and_______________

  1. Is drier than subsoil

  2. Is richer in Na and Mg

  3. Is wetter than subsoil

  4. Contains more organic matter
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • The topsoil is darker because it contains dead organic material in many stages of decomposition. 
  • This degradation produces a substance called humus that is composed of carbon-rich compounds and imparts a dark color. Thus, the correct answer is option D.
Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Which of the following present in the soil is most helpful to the growth of plants?

  1. Gravel

  2. Humus

  3. Sand

  4. Silt
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Humus is organic matter containing nutrients from the soil. It is nothing but dead and decaying organic matter where saprophytes convert complex organic material into simple nutrients. These nutrients are then available to the plants through humus.

So, option B is the correct answer.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Water infiltration will be slowest in

  1. Black cotton soil

  2. Sandy soil

  3. Red soil

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

Black cotton soil is rich in clay, which has very small sized particles. These small sized particles obstruct water movement and hence, this soil has high water holding capacity and low percolation.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Salinity of the soil is often caused due to

  1. Accumulation of soluble minerals near or in the surface in arid region

  2. Excessive addition of water

  3. Rapid evaporation of surface water

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

Soil salinity is the presence of excess salts especially those of sodium, potassium and magnesium. 

Soil salinity is caused by- 
(i) Soil formation from rocks having excess of sodium, calcium, magnesium etc. 
(ii) Nearness to sea shore, salt lake or salt mine. 
(iii) Irrigation with water rich in basic salts. 
(iv) Absence of slope or presence of basin-shaped topography. 
(v) Elevated water table with aridity. 
When minerals accumulate near surface of arid regions, soil becomes saline
So, the correct answer is 'Accumulation of soluble minerals near or in the surface in arid region'

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

The type of soil which can hold water for more time have 

  1. Lower percolation rate

  2. Higher percolation rate

  3. Intermediate percolation rate

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

Percolation rate of a soil is the water absorption rate of the soil. It depends on the composition of the soil. It is different for different types of soil. Hence, it helps in selection of proper soil for the crop growth. Soil with lower percolation has high water retention capacity whereas soil with high percolation has low water retention capacity. Lower percolation rate refers that the soil can hold water for more time while higher percolation rate refers that the soil can hold water for less time. 

Thus, the correct answer is option A. 

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Good soil is the one which

  1. Allows water to percolate slowly

  2. Allows water to pass quickly

  3. Allows limited amount of water into it

  4. Holds whole of water entering it
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Good agricultural soil should allow water to percolate slowly so that it remains available to plant roots for a longer duration, rather than draining away too quickly or waterlogging.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

A fertile agricultural soil appears deep coloured at the surface as compared to soil one metre down. The reason for colour of top soil is

  1. More moisture

  2. Rich in organic matter

  3. Rich in iron, calcium and magnesium

  4. Recent formation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The dark color of topsoil is primarily due to the presence of humus, which is decomposed organic matter.

Multiple choice biology soil : our life soil properties soil - properties basics of soil pollution

Most friable soil is

  1. Sand

  2. Clay

  3. Loam

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

Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz making it most friable.