Soil Profile and Horizons

Questions and Answers

Match the following soil horizons with their characteristics:

A – Horizon = Top layer of soil rich in minerals and humus B – Horizon = Sub-soil with larger rock particles and less humus C – Horizon = Sub-stratum made of broken rocks from weathering Bed – rock = Unweathered solid rock beneath soil layers

Match the following descriptions with the correct soil horizon:

A – Horizon = Soft, porous, and holds more water B – Horizon = Lighter in color and harder than top soil C – Horizon = Formation from the partial weathering of bed-rock Bed – rock = Source of soil produced over a long period

Match the following soil horizons with their alternate names:

A – Horizon = Top soil B – Horizon = Sub-soil C – Horizon = Sub-stratum Bed – rock = Parent rock

Match the following soil horizons with their fertility levels:

<p>A – Horizon = Most fertile B – Horizon = Less fertile than top soil C – Horizon = Least fertile Bed – rock = Not fertile</p> Signup and view all the answers

Match the following soil horizons with the living organisms they contain:

<p>A – Horizon = Insects, worms, bacteria B – Horizon = Very few living organisms C – Horizon = Largely devoid of life Bed – rock = No living organisms</p> Signup and view all the answers

Study Notes

Soil Profile Overview

A vertical section through soil layers is referred to as a Soil Profile.
Soil Profile contains three distinct layers, known as Horizons: A, B, and C.

A – Horizon (Top Soil)

The topmost layer, known as A – Horizon or Top Soil.
Characterized by dark color, rich in minerals and humus.
Essential for plant roots; it supports their growth.
Hosts diverse living organisms, including insects (ants, beetles), earthworms, rodents, and microbial life (bacteria and fungi).
Contains decayed organic matter from dead plants and animals, adding to its fertility.
Soft and porous texture allows it to retain moisture effectively.
Provides essential nutrients and minerals, making it the most valuable soil layer for plants.

B – Horizon (Sub-Soil)

Located directly beneath the A – Horizon, this layer is known as B – Horizon or Sub-Soil.
Composed of larger rock particles compared to A – Horizon.
Typically lighter in color, harder, and more compact.
Has a limited presence of living organisms.
Some tree roots can extend into this layer, though it is much less fertile than the top soil.
Contains minimal humus, contributing to its lower fertility.

C – Horizon (Sub-Stratum)

Positioned below the B – Horizon, referred to as C – Horizon or Sub-Stratum.
Made of small lumps of broken rock created by the partial weathering of bedrock (parent rock).
The rock in this layer continues to break down into finer particles.
Beneath the C – Horizon lies unweathered Solid Rock known as Bed-Rock, which has formed soil over long periods.

Influential Climatic Factors

Key climatic factors include wind, temperature, rainfall, light, and humidity.
These factors play a significant role in affecting soil profiles and impacting soil structure.

Description

This quiz explores the concept of soil profiles, focusing on the three key layers known as horizons: A, B, and C. It delves into the characteristics, depth, color, and composition of each layer, particularly emphasizing the topsoil (A-horizon) and its significance in soil health. Test your knowledge on soil structure and composition!