Soil Composition and Texture Quiz

Soil Composition

• Soil is a mixture of solid, liquid, and gas.
• The solid component includes mineral grains and biological material.
• Soil is a product of weathering processes.
• It supports plant growth by providing water and nutrients.
• Gases like carbon dioxide, methane, and oxygen fill the spaces within the soil.
• Soil is a semi-non-renewable resource, taking a long time to accumulate nutrients and water.

Soil Texture

• Soil texture refers to the proportion of clay, silt, and sand particles.
• Humus, partially decayed organic matter in soil, is critical for soil fertility.

Soil Texture Triangle

• A diagram that helps determine soil type based on its composition (clay, silt, and sand percentages).

Four Main Characteristics of Soil

• Soil depth: The thickness from the surface to a root-limiting layer (like bedrock or seasonal water table).
• Soil texture: The relative proportions of sand, silt, and clay, affecting characteristics like porosity, drainage, and permeability.
• Soil structure: The shape and size of soil aggregates—the clumps or grains.
• Organic matter: The amount of organic material within the soil, impacting soil characteristics.

Soil Profile

• A sequence of soil horizons from the surface down to bedrock.
• Each horizon has distinct physical, chemical, and biological characteristics.

Soil Horizons

• O horizon: Contains organic matter, usually dark-colored.
• A horizon: Typically dark due to the presence of humus.
• E horizon: A light-colored layer sometimes present in forest areas.
• B horizon: Brownish or reddish; leached materials from above have accumulated here.
• C horizon: Made up of parent material (bedrock) in varying stages of weathering.

Soil Quality and Poor Soil Management

• Soil quality is a soil's ability to sustain biological productivity, maintain environmental quality, and promote plant and animal health. Human activities can significantly affect soil quality.
• Soil Pollution: occurs when soil particles are detached, transported, and deposited. Can occur naturally or from human activities.
• Erosion: the removal of soil particles; can be accelerated by removing plants and trees.
• Desertification: The degradation of productive land in arid and semi-arid areas.
• Acidification: Soil becomes more acidic due to the build-up of acidic cations (hydrogen, aluminum, iron, and manganese). Fertilizers (like anhydrous ammonia) can accelerate this.
• Salinization: Accumulation of salt on the soil surface, harming plant growth.
• Deforestation: Removing trees and vegetation negatively impacts the soil.
• Heavy metal contamination: A toxic build-up that impacts plant and microbial life in the soil.
• Eutrophication: Excessive nitrogen and phosphorus (from fertilizers) build up in water bodies, leading to algal blooms and harming the ecosystem.
• Bedrock: Solid unweathered rock.