Soil Classification Chapter 3 Flashcards

Questions and Answers

Why do we classify soils?

To take advantage of research and experience at one location to predict the behavior of similar soil in another and to tell us what is where.

What classification system is used in the USDA-NRCS system?

Local classification

USDA-NRCS system (correct)

European classification

FAO classification

What does F.A.O stand for?

Food and Agriculture Organization

What are the 5 factors of soil development represented by CLORPT?

Climate, Organism, Relief, Parent Material, Time Signup and view all the answers

What are the 6 levels of Soil Taxonomy?

Order, Suborder, Great group, Sub-group, Family, Series Signup and view all the answers

What is Muck?

Black material in which decomposition is much more complete and the organic matter is highly humidified. Signup and view all the answers

How many soil orders are there?

12 Signup and view all the answers

Soil orders are based on what?

Their significant effect on the land use or management of all soils in that order. Signup and view all the answers

How many soil series are classified in Texas?

1,300+ Signup and view all the answers

What do soil order names all contain?

'sols', Latin for solum, meaning soil. Signup and view all the answers

Which soil order is productive for crops and can hold water?

Alfisols Signup and view all the answers

What is the definition of Andisols?

Soils that generate minerals with little crystalline structure, high water and nutrient holding capacity, and are commonly found in cool areas. Signup and view all the answers

What are Aridisols typically characterized by?

Dry conditions, lack of moisture, and accumulation of gypsum, salt, and calcium carbonate. Signup and view all the answers

What defines Entisols?

Soils with no pedogenic horizon development found in areas of recently deposited parent materials. Signup and view all the answers

What are Gelisols characterized by?

Permafrost near the soil surface and no cryoturbation. Signup and view all the answers

What are Histosols rich in?

High content of organic matter. Signup and view all the answers

What are the characteristics of Mollisols?

Dark colored surface horizon with high organic matter, forming under grass climates. Signup and view all the answers

What defines Oxisols?

Highly weathered soils in tropical and subtropical regions. Signup and view all the answers

What are Spodosols typically found under?

Coarse-textured deposits under coniferous forests. Signup and view all the answers

What are Ultisols known for?

Forming in humid areas with fairly intense weathering and low nutrient retention. Signup and view all the answers

What are Vertisols characterized by?

Expanding clay minerals and cracks that open and close periodically. Signup and view all the answers

What is a soil Series?

Based on a range of properties and named for the location where it was first identified. Signup and view all the answers

What is the Texas state soil?

Houston Black Soil Signup and view all the answers

What is a key technique for mapping soil?

Using soil pits to examine various soil characteristics. Signup and view all the answers

What is a soil Survey?

A systematic examination, description, classification, and mapping of soil in a given area. Signup and view all the answers

What do Land Capability Classes range from?

Classes I-VIII (1-8) Signup and view all the answers

What defines Class I land capability?

Wide range of plants, low erosion hazard, deep, well-drained, and easily worked. Signup and view all the answers

What is the limitation of Class 2 land?

Requires careful soil management but has few limitations. Signup and view all the answers

What is Prime farmland?

Land classified as Class I and II, best for producing food and fiber. Signup and view all the answers

What are the characteristics of Class 4 land?

More limited plant choices and requires careful management. Signup and view all the answers

Class 5 land capability has limitations that restrict what?

The kind of plants that can be grown. Signup and view all the answers

What is the main characteristic of Class 6 land?

Not suited for cultivated crops but adapted to special crops. Signup and view all the answers

What does Class 7 land indicate?

Impractical to apply pasture or range improvements. Signup and view all the answers

What does Class 8 land imply?

Cannot be expected to return significant benefits from management. Signup and view all the answers

What is Permafrost?

Soil, rock, or sediment that is frozen for more than two consecutive years. Signup and view all the answers

Study Notes

Soil Classification Overview

Soil classification helps predict soil behavior and manage land effectively.
The USDA-NRCS classification system is used in over 50 countries worldwide.

Soil Development Factors

CLORPT is an acronym for the five factors of soil development: Climate, Organism, Relief, Parent Material, and Time.

Soil Taxonomy Structure

Soil taxonomy contains six levels: Order, Suborder, Great Group, Sub-group, Family, and Series.

Types of Soil

Muck: Decomposed material with high humidity content.
Soil orders represent the most general classification category.

Texas Soil Series

Over 1,300 soil series identified in Texas, classified into nine soil orders.
Seven prominent orders include Alfisols, Aridisols, Entisols, Inceptisols, Mollisols, Ultisols, and Vertisols.

Soil Order Characteristics

Alfisols: Nutrient-rich, productive for crops, comprise about 10% of global land.
Andisols: Volcanic glass content, high water retention, make up about 1% of global land.
Aridisols: Found in desert areas, low moisture, make up 12% of global land.
Entisols: Recently formed soils lacking horizon development, make up 16% of global land.
Gelisols: Contain permafrost, found in cold regions, comprise 9% of global land.
Histosols: Organic-rich, saturated soils, found in bogs and wetlands, make up 1% of global land.
Inceptisols: Moderately weathered, diverse characteristics, make up 17% of global land.
Mollisols: Dark soil, high organic content, found primarily in grasslands, make up 7% of global land.
Oxisols: Highly weathered, found in tropical areas, make up 8% of global land.
Spodosols: Acidic subsoils found under coniferous forests, make up 4% of global land.
Ultisols: Formed in humid areas, susceptible to weathering, make up 8% of global land.
Vertisols: Have shrink-swell clay, high fertility, make up about 25% of global land.

Mapping and Assessment Techniques

Soil series characterized by a range of properties, named for first identification location.
Houston Black Soil designated as the Texas State Soil.
Soil surveys involve systematic examination and mapping of soil characteristics.
Soil pits allow detailed examination of soil profiles, including color, texture, and structure.

Land Capability Classes

Class I: Versatile, low erosion risk, deep, well-drained soils suitable for a variety of crops.
Class II: Requires careful management; few limitations for crops.
Class III: Designated as prime farmland for producing food and fiber.
Class IV: Limited plant choices and requires careful management.
Class V: Soil limitations restrict certain crops; often wet or stony.
Class VI: Unsuitable for crops but viable for special uses like orchards.
Class VII: Impractical for management improvements in pastures or ranges.
Class VIII: Unproductive for crops but may allow recreational activities.

Permafrost

Defined as soil, rock, or sediment frozen for over two consecutive years, typically found in extremely cold climates.

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Description

This quiz focuses on the classification of soils as outlined in Chapter 3. It covers key terms and definitions related to soil classification systems including USDA-NRCS and the factors affecting soil development. Perfect for students seeking to deepen their understanding of soil science concepts.