Ch 9 covers how soil is formed, the soil profile (layers), types of soil (sandy, clayey, loamy), and the importance of soil conservation to prevent erosion.
Soil is formed by weathering of rocks over millions of years. The soil profile has layers: A-horizon (topsoil — dark, rich in humus), B-horizon (less organic matter, more minerals), C-horizon (partially broken rock), and bedrock.
Sandy soil: large, loose particles, high percolation (water drains fast), poor water retention. Clayey soil: very fine particles, holds water well, used for pottery. Loamy soil: mixture of sand, clay, and silt — ideal for most crops as it holds water and has air spaces.
Download: https://ncert.nic.in/textbook/pdf/gesc109.pdf | Complete book: https://ncert.nic.in/textbook/pdf/gesc1ps.zip
Humus is the dark, organic component of the topsoil formed by decomposition of dead plants and animals. It makes the soil fertile by providing nutrients, improves soil structure, and increases its water-holding capacity.
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