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Tamil Nadu Board of Secondary EducationHSC Science Class 12

What is soil profile? Explain the characters of different soil horizons.

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Question

What is the soil profile? Explain the characters of different soil horizons.

Chart
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Solution

Horizon Description
O-Horizon (Organic horizon) Humus SamacheerKalvi.Guru It consists of fresh or partially decomposed organic matter. 01 - Freshly fallen leaves, twigs, flowers, and fruits. O2 - Dead plants, animals, and their excreta decomposed by micro-organisms. Usually absent in agricultural and deserts.
A-Horizon (Leached horizon) Topsoil - Often rich in humus and minerals. It consists of topsoil with humus, living creatures, and in-organic minerals. A1 - Dark and rich in organic matter because of the mixture of organic and mineral matters. A2 - Light-colored layer with large-sized mineral particles.
B-Horizon (Accumulation horizon) (Subsoil - Poor in humus, rich in minerals) It consists of iron, aluminum, and silica-rich clay organic compounds.
C - Horizon (Partially weathered horizon) Weathered rock Fragments - Little or no plant or animal life. It consists of parent materials of soil, composed of a little amount of organic matter without life forms.
R Horizon (Parent material) Bedrock It is a parent bedrock upon which underground water is found.
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Dispersal of Fruits and Seeds
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Chapter 6: Principles of Ecology - Evaluation [Page 132]

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Samacheer Kalvi Biology (Botany) [English] Class 12 TN Board
Chapter 6 Principles of Ecology
Evaluation | Q 50 | Page 132
Samacheer Kalvi Botany [English] Class 12 TN Board
Chapter 6 Principles of Ecology
Evaluation | Q 50 | Page 160

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