NCERT Book Class 7 Science Soil

9 Soil

Soil is one of the most important natural resources. It supports the growth of plants by holding the roots firmly and supplying water and nutrients. It is the home for many organisms. Soil is essential for agriculture. Agriculture provides food, clothing and shelter for all. Soil is thus an inseparable part of our life. The earthy fragrance of soil after the first rain is always refreshing.

9.1 SOIL TEEMING WITH LIFE

One day during the rainy season Paheli and Boojho observed an earthworm coming out of the soil. Paheli wondered whether there were other organisms also in the soil. Let us find out.

Activity 9.1

Collect some soil samples and observe them carefully. You can use a hand lens. Examine each sample carefully and fill in Table 9.1.

•  Discuss your observations with your friends.
•  Are the soil samples collected by your friends similar to the ones collected by you?

Boojho and Paheli have used soil in many ways. They enjoy playing with it. It is a great fun indeed.

Make a list of the uses of soil

Exercises

Tick the most suitable answer in questions 1 and 2.

1. In addition to the rock particles, the soil contains

(i) air and water

(ii) water and plants

(iii) minerals, organic matter, air and water

(iv) water, air and plants

2. The water holding capacity is the highest in

(i) sandy soil

(ii) clayey soil

(iii) loamy soil

(iv) mixture of sand and loam

3. Explain how soil is formed.

4. How is clayey soil useful for crops?

5. List the differences between clayey soil and sandy soil.

7. Sketch the cross section of soil and label the various layers.

7. Razia conducted an experiment in the field related to the rate of percolation. She observed that it took 40 min for 200 mL of water to percolate through the soil sample. Calculate the rate of percolation

Please refer to attached file for NCERT Class 7 Science Soil