Soil is the uppermost layer of the earth. It is formed due to weathering of rocks by various external factors such as air, water and wind. The soil also contains various living and dead substances of plants and animals called humus. The soil has a lot of nutrients that help in the growth of plants.

Match the following: Column A Column B 1. Runoff i. Check soil erosion 2. Dead leaves ii. Silt 3. Slash and burn iii. Humus 4. Dams iv. Farming technique

1-ii Silt is the granular fine clay or sand which gets deposited in river bank, valleys due to runoff of water. 2-iii The dead leaves of plants decay and form a highly fertile top layer of soil called the humus. 3-iv Slash-and-burn agriculture is often used by tropical-forest root-crop farmers in various parts of the world. It involves the cutting and burning of plants in a forest or woodland to create a field. 4-i Soil erosion is the removal of the uppermost layer of the soil. The dams hold the water and lower the rates of water flow in rivers thereby lowering the rate of soil erosion by water run-off. Column A Column B 1. Runoff ii. Silt 2. Dead leaves iii. Humus 3. Slash and burn iv. Farming technique 4. Dams i. Check soil erosion