CBSE NCERT Solutions for Class 7 Science Chapter 9

CBSE NCERT Solutions for Class 7 Science Chapter 9 Soil or अध्याय 9 मृदा in हिंदी मीडियम free PDF download or View online or View in Video Format based on latest NCERT Books and NCERT Solutions Apps for new academic session 2019 – 2020. Visit to Discussion Forum to Share Your View with your friends.


Class:7
Subject:Science – विज्ञान
Chapter 9:Soil

CBSE NCERT Solutions for Class 7 Science Chapter 9

Soil: Question – Answers

7 Science Chapter 9: Soil

CBSE NCERT Solutions for Class 7 Science Chapter 9 Soil is given below to use online or View in Video Format. Download links are given at the Top of the page. Visit to हिंदी मीडियम or Class 7 Science main page.

CBSE NCERT Solutions for Class 7 Science Chapter 9 Soil




CBSE NCERT Solutions for Class 7 Science Chapter 9 Soil in PDF form
7 Science chapter 9 answers

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7 विज्ञान अध्याय 9 अभ्यास के प्रश्न उत्तर





NCERT Solutions for Class 7 Science अध्याय 9: मृदा in हिंदी मीडियम is given below. Visit to English Medium or  Class 7 Science main page.

NCERT Solutions for Class 7 Science अध्याय 9: मृदा
class 7 science
class 7 science chapter 9 answers

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7 Science Chapter 9 Sols in Video

NCERT Solutions for class 7 Science Chapter 9 explanation with question answers in video format with complete description. Download 7th Class App for offline use.




Important Questions with Answers
  1. Soil conservation measures are mainly aimed at protecting which of the following?
    (a) Plants
    (b) Top soil
    (c) Sub soil
    (d) Soil organisms
  2. The microorganisms present in the soil require moisture (water) and nutrients for growth and survival. Choose from the options below the habitat (place) where the soil has plenty of water and nutrients.
    (a) Desert
    (b) Forest
    (c) Open field
    (d) Cricket ground
  3. Read the following statements with reference to soil.
    (i) Weathering is a very fast process of soil formation.
    (ii) Percolation of water is faster in sandy soils.
    (iii) Loamy soil contains only sand and clay.
    (iv) Top soil contains the maximum amount of humus.
    Choose the correct statements from the above.
    (a) (ii) and (iv)
    (b) (i) and (iii)
    (c) (ii) and (iii)
    (d) (i) and (ii)
  4. Availability of water and minerals in the soil for maximum absorption by roots is in the–
    (a) B-horizon
    (b) C-horizon
    (c) A-horizon
    (d) surface of soil
  5. Read the following statements and give the appropriate terms for each of them.
    (a) The process of breakdown of rocks by the action of wind, water, sunlight.
    (b) Removal of top soil during heavy rains or strong winds.
    (c) Accumulation of wastes in the soil generated by human activity which alter the features of soil.
    (d) The process of movement of water into deeper layers of soil.
  6. Which of the following situations – ‘A’ or ‘B’ – is advantageous for absorption of water and minerals? Why?
    Situation ‘A’: Growth and branching of roots in the C-horizon.
    Situation ‘B’: Growth and branching of roots in A and B horizons.
  7. A man digging a pit found that he could dig with ease initially but digging became difficult as he went deeper. He could not dig beyond a depth of 5 feet. Provide a suitable scientific explanation.



Answers
  • 1 (b)
  • 2 (b)
  • 3 (a)
  • 4 (c).
  • 5. (a) Weathering (b) Erosion (c) Soil pollution (d) Percolation
  • 6. Situation ‘B’ is advantageous to plants because A- and B- horizons are rich in water, minerals and humus.
  • 7. The soil surface has loose top soil which is easier to dig. At deeper layers, partially weathered rocks or bedrocks are present, which are hard making digging difficult.

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समझाइए कि मृदा कैसे बनती है?

चट्टानों के अपक्षय से मिट्टी का निर्माण होता है। तूफान, वायु और जल की क्रिया द्वारा चट्टानों का धीरे-धीरे टूटती रहती हैं। मिट्टी का निर्माण एक धीमी प्रक्रिया है। यह हर समय होता रहती है। मिट्टी का निर्माण दो चरणों वाली प्रक्रिया है:
चट्टानों का अपक्षय होता है अर्थात चट्टान छोटे कणों में टूट जाती है।
ये छोटे कण ह्यूमस (कार्बनिक पदार्थ) के साथ मिलकर मृदा बनाते हैं।

How is clayey soil useful for crops?

Clayey soil is rich in humus and are very fertile, so it is suitable for growing cereals like wheat and gram. Such soil is good at retaining water.
For paddy, soils rich in clay and organic matter and having a good capacity to retain water are ideal. For lentils (masoor) and other pulses, loamy soils, which drain water easily, are required.

Describe the cross section of soil and its various layers.

A vertical section through different layers of the soil is called the soil profile. Each layer differs in feel (texture), colour, depth and chemical composition. These layers are referred to as horizons.
The uppermost horizon is generally dark in colour as it is rich in humus and minerals. The humus makes the soil fertile and provides nutrients to growing plants. This layer is generally soft, porous and can retain more water. It is called the topsoil or the A-horizon.
The next layer has a lesser amount of humus but more of minerals. This layer is generally harder and more compact and is called the B-horizon or the middle layer.
The third layer is the C-horizon, which is made up of small lumps of rocks with cracks and crevices.
Below this layer is the bedrock, which is hard and difficult to dig with a spade.

मृदा प्रदूषण को किस प्रकार रोका जा सकता है?

मृदा प्रदूषण की रोकथाम:
रासायनिक उर्वरकों के बजाय खाद का उपयोग करें।
औद्योगिक कचरे को संशोधित करने के बाद ही उसे फेंका जाना चाहिए।
पॉलिथीन और प्लास्टिक के उपयोग से बचें या उन्हें मिट्टी में नहीं मिलाना चाहिए।

मृदा अपरदन को किस प्रकार रोका जा सकता है?

मृदा अपरदन की रोकथाम:
कटे हुए वनों के स्थान पर बड़े पैमाने पर रोपण।
घास भूमि के चराई पर रोक।
पहाड़ी क्षेत्रों में सीढ़ीदार खेत बनाकर खेती करना।