Soil Flashcards
What are the three soil particles, from largest to smallest?
Sand > Silt > Clay
What is loam?
A balanced mix of sand, silt, and clay—ideal for most plant growth.
Why is soil texture important?
It affects water retention, drainage, aeration, and root penetration.
What does soil structure refer to?
The arrangement of soil particles into aggregates or ‘peds.’
How does structure affect soil function?
Good structure improves water movement and root growth; poor structure can lead to compaction and runoff.
What pH range is best for most plants?
6.0–7.5
What happens in soils that are too acidic or too alkaline?
Nutrient availability decreases and plant growth is affected.
What does nitrogen do for plants?
Promotes leafy green growth.
What does phosphorus do?
Encourages root development and flowering.
What does potassium do?
Improves disease resistance and overall plant health.
Name 3 types of soil organisms and one benefit of each.
- Bacteria – Decompose organic matter, cycle nutrients
- Earthworms – Aerate soil and improve structure
- Fungi – Form mycorrhizae to help plant roots absorb nutrients
What role do decomposers play in soil?
Break down organic matter into humus and release nutrients.
What is humus?
Fully decomposed organic material—very stable and nutrient-rich.
What land class is best for farming?
Class I (few limitations)
What do Class V–VIII lands usually require?
They are not suited for cultivation—better for pasture, woodland, or wildlife habitat.
What does the LCC system measure?
A land’s ability to support agriculture without causing damage.
What are the 3 main types of water erosion?
Sheet, Rill, Gully
What causes accelerated erosion?
Poor land management, overgrazing, deforestation, construction
Name 3 Best Management Practices to prevent erosion.
- Contour farming
- Cover crops
- No-till agriculture
What is a buffer strip?
A vegetated area next to water bodies to trap sediment and filter runoff.
What information does a soil survey provide?
Soil types, drainage, fertility, limitations, and recommended land use.
Why is understanding drainage class important in soil surveys?
It tells how water moves through the soil and helps guide land use decisions.
What’s the purpose of a soil map?
To visually show different soil types and their locations in a region.
What are the 5 soil-forming factors?
- Parent material
- Climate
- Biota
- Topography
- Time
What is parent material?
The original geological material from which soil forms.
How does topography affect soil formation?
Steep slopes lose soil to erosion; flat areas may accumulate water.
What is weathering?
The breakdown of rock into smaller particles by physical or chemical processes.
What is the composition of average soil?
- 45% mineral particles
- 25% water
- 25% air
- 5% organic matter
What is texture based on in soil?
The size of particles—sand (largest), silt, and clay (smallest).
What is soil structure?
How particles group together, affecting water movement, root growth, and air flow.
What does soil pH indicate?
Acidity or alkalinity, impacting nutrient availability to plants.
What is porosity in soil?
Spaces between soil particles, important for air and water movement.
What is organic matter in soil?
Includes decaying plants and animals, helps with fertility and water retention.
What is the role of soil organisms?
Break down organic material, cycle nutrients, improve soil structure.
What is sedimentation?
Soil ends up in rivers and lakes, hurting ecosystems.
What is contour farming?
Planting along slope lines to prevent erosion.
What is no-till farming?
Minimizes disturbance to the soil.
What does the term ‘well-drained’ mean in soil surveys?
Indicates how easily water moves through the soil.
What is the impact of disturbed soil ecosystems?
Leads to changes in soil structure and nutrient cycling.
What is the function of buffer strips?
To catch runoff and protect water bodies from sediment.
