Chapter- 11 Soil resource - Page |1
Chapter – 7
Soil Resources
Q.1
a. What is the soil? Name the four types of soil.
i. The thin layer of loose mixture of small rock particles and rotting organic matter that covering the
surface of the earth is called as Soil
ii. The four type of soils are: Alluvial soil, Black soil, Red soil and Laterite soil
b. State any two factors responsible for the formation of soil.
i. The forces of nature like the changing of temperature, running water and wind,
ii. And the chemical and organic changes are the factors responsible for the formation of soil.
c. Give geographical reasons for the following:
i. The colour of alluvium varies in different areas.
a. The colour of alluvium allvium is depend up on factors like, the depth of deposition, the
texture of the materials,
b. The time taken for the soil to mature and the presence of different minerals and organic
content are the reason for the colour variation of alluvium.
ii. Khadar is more fertile than bhangar soil.
a. Because it consists of new, fine-grained alluvial soil deposited annually by river floods, it is
renewed every year by fresh silt brought by floods, keeping it highly fertile.
b. Composed of fine silt and clay, it retains more moisture and nutrients and are generally
free from calcareous kankar deposits.
c. Bhangar soil found in higher, non-flooded terraces, and contains high concentrations of
these lime nodules, which reduce fertility.
iii. Black soil has a kind of self-ploughing characteristic
a. Black soil is called "self-ploughing" because its high clay content. Therefore becomes very
sticky and swells during the rainy season.
b. While it dries, the soil shrinks and thus forming large, deep cracks. Through these cracks
oxygen reaches to the deeper layers.
c. The cracks allow the surface soil which is rich in organic matter to fall into the lower
layers and mixing the nutrients without the need of human intervention.
d. This process enhances aeration to the deep soil, improves the soil fertility, and making
black soil ideal for agriculture.
d. (i). How can you say that soil has evolved over millions of years?
a. Formation of soil is a long process, it takes millions of years to form a few centimeters of
soil because,
b. Soil is formed by the weathering of rocks and minerals; it takes a very long time for the
breaking down of rock with the wind, water, temperature changes, and chemical
processes.
c. Over millions of years, different layers of soil, called as the horizons, develop as the
minerals from the organic matters accumulate by leaching.
d. These factors collectively show soil is not a static entity but an evolving natural resource
shaped over long geological periods.
(ii). Name one important constituent of soil that adds fertility to the soil.
a. Soil fertility refers to the strength of the soil to support plant life.
, Chapter- 11 Soil resource - Page |2
b. The important component that adds fertility to the soil are nitrogen, phosphorus and
Potassium, which are the basic necessary components of plant nourishment.
Q. 2
a. How are alluvial soil formed?
i. This soil is formed by the sediments brought down by rivers.
ii. The rivers deposit these very fine particles of silt in the river basins, which is a mixture of sand,
clay and silt called loam.
iii. This soil is rich in potash, phosphoric acid, and lime. And commonly found in river basins,
floodplains, and delta regions.
iv. The entire northern plains are made up of alluvial soil by the depositional activities of the three
important Himalayan Rivers.
b. Mention any two advantages of alluvial soil.
i. High Fertility: As it is deposited by rivers, it is rich in nutrients and humus, making it ideal for
supporting a wide variety of Rabi and Kharif crops.
ii. Good Water Retention: It has an excellent capacity to hold water, which is crucial for the
cultivation of crops requiring significant moisture, such as rice and sugarcane.
c. Give geographical reasons for the following:
i. Different regions in India have different kinds of soil for agriculture.
a. Different regions in India have different kinds of soil for agriculture because; India is a vast
region with varied natural environment.
b. It has several physiographic regions and different types of climate.
ii. Alluvial soil varies in texture.
a. The velocity of the transporting river and the distance the sediments travels has a great
role in the formation of the texture of alluvial soil.
b. In the upper reaches of the river valley the texture of the soil is dry, coarse, porous and
sandy and consists of clay and organic matters. Soil particles here are larger and non-
uniform.
c. Further down to the river valley, the soil particles become smaller and more uniform. And
they are more compact, less coarse, and moister.
iii. Nearly all types of crops grow well in riverine soils.
a. All types of crops grow well in the riverine or the alluvial soils because they are highly
fertile, nutrient-rich, and possess ideal texture for agriculture.
b. This type of soil is deposited by rivers, this soil contains rich minerals, particularly potash,
phosphoric acid, and lime.
c. Its, loamy, porous, and moisture-retentive nature allows easy cultivation and excellent
root penetration for a variety of crops.
d. (i). Why is soil a valuable resource for India?
a. Soil is a critically valuable, renewable resource for India because it forms the foundation of
the country's agrarian economy, supporting food security for over a billion people.
b. It provides essential nutrients for crop growth, acts as a natural water filter, supports
biodiversity, and serves as a carbon sink.
c. Effective management and conservation of this resource are crucial for sustainable
development and environmental health. ,.
(ii). Why is black soil considered a productive soil?
a. Black soil or the Regur soil is considered highly productive because, it contains 50
percent clay which helps the soil to absorb and loos moisture slowly and allowing
Chapter – 7
Soil Resources
Q.1
a. What is the soil? Name the four types of soil.
i. The thin layer of loose mixture of small rock particles and rotting organic matter that covering the
surface of the earth is called as Soil
ii. The four type of soils are: Alluvial soil, Black soil, Red soil and Laterite soil
b. State any two factors responsible for the formation of soil.
i. The forces of nature like the changing of temperature, running water and wind,
ii. And the chemical and organic changes are the factors responsible for the formation of soil.
c. Give geographical reasons for the following:
i. The colour of alluvium varies in different areas.
a. The colour of alluvium allvium is depend up on factors like, the depth of deposition, the
texture of the materials,
b. The time taken for the soil to mature and the presence of different minerals and organic
content are the reason for the colour variation of alluvium.
ii. Khadar is more fertile than bhangar soil.
a. Because it consists of new, fine-grained alluvial soil deposited annually by river floods, it is
renewed every year by fresh silt brought by floods, keeping it highly fertile.
b. Composed of fine silt and clay, it retains more moisture and nutrients and are generally
free from calcareous kankar deposits.
c. Bhangar soil found in higher, non-flooded terraces, and contains high concentrations of
these lime nodules, which reduce fertility.
iii. Black soil has a kind of self-ploughing characteristic
a. Black soil is called "self-ploughing" because its high clay content. Therefore becomes very
sticky and swells during the rainy season.
b. While it dries, the soil shrinks and thus forming large, deep cracks. Through these cracks
oxygen reaches to the deeper layers.
c. The cracks allow the surface soil which is rich in organic matter to fall into the lower
layers and mixing the nutrients without the need of human intervention.
d. This process enhances aeration to the deep soil, improves the soil fertility, and making
black soil ideal for agriculture.
d. (i). How can you say that soil has evolved over millions of years?
a. Formation of soil is a long process, it takes millions of years to form a few centimeters of
soil because,
b. Soil is formed by the weathering of rocks and minerals; it takes a very long time for the
breaking down of rock with the wind, water, temperature changes, and chemical
processes.
c. Over millions of years, different layers of soil, called as the horizons, develop as the
minerals from the organic matters accumulate by leaching.
d. These factors collectively show soil is not a static entity but an evolving natural resource
shaped over long geological periods.
(ii). Name one important constituent of soil that adds fertility to the soil.
a. Soil fertility refers to the strength of the soil to support plant life.
, Chapter- 11 Soil resource - Page |2
b. The important component that adds fertility to the soil are nitrogen, phosphorus and
Potassium, which are the basic necessary components of plant nourishment.
Q. 2
a. How are alluvial soil formed?
i. This soil is formed by the sediments brought down by rivers.
ii. The rivers deposit these very fine particles of silt in the river basins, which is a mixture of sand,
clay and silt called loam.
iii. This soil is rich in potash, phosphoric acid, and lime. And commonly found in river basins,
floodplains, and delta regions.
iv. The entire northern plains are made up of alluvial soil by the depositional activities of the three
important Himalayan Rivers.
b. Mention any two advantages of alluvial soil.
i. High Fertility: As it is deposited by rivers, it is rich in nutrients and humus, making it ideal for
supporting a wide variety of Rabi and Kharif crops.
ii. Good Water Retention: It has an excellent capacity to hold water, which is crucial for the
cultivation of crops requiring significant moisture, such as rice and sugarcane.
c. Give geographical reasons for the following:
i. Different regions in India have different kinds of soil for agriculture.
a. Different regions in India have different kinds of soil for agriculture because; India is a vast
region with varied natural environment.
b. It has several physiographic regions and different types of climate.
ii. Alluvial soil varies in texture.
a. The velocity of the transporting river and the distance the sediments travels has a great
role in the formation of the texture of alluvial soil.
b. In the upper reaches of the river valley the texture of the soil is dry, coarse, porous and
sandy and consists of clay and organic matters. Soil particles here are larger and non-
uniform.
c. Further down to the river valley, the soil particles become smaller and more uniform. And
they are more compact, less coarse, and moister.
iii. Nearly all types of crops grow well in riverine soils.
a. All types of crops grow well in the riverine or the alluvial soils because they are highly
fertile, nutrient-rich, and possess ideal texture for agriculture.
b. This type of soil is deposited by rivers, this soil contains rich minerals, particularly potash,
phosphoric acid, and lime.
c. Its, loamy, porous, and moisture-retentive nature allows easy cultivation and excellent
root penetration for a variety of crops.
d. (i). Why is soil a valuable resource for India?
a. Soil is a critically valuable, renewable resource for India because it forms the foundation of
the country's agrarian economy, supporting food security for over a billion people.
b. It provides essential nutrients for crop growth, acts as a natural water filter, supports
biodiversity, and serves as a carbon sink.
c. Effective management and conservation of this resource are crucial for sustainable
development and environmental health. ,.
(ii). Why is black soil considered a productive soil?
a. Black soil or the Regur soil is considered highly productive because, it contains 50
percent clay which helps the soil to absorb and loos moisture slowly and allowing
