classification of soils
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Classification of Soils. Introduction to Agriculture. What will we learn today?. How do we classify soils? What is a soil profile? What is a land capability class? What is the Soil Classification System?. Soil Profile. - PowerPoint PPT PresentationTRANSCRIPT
Classification of Soils
Introduction to Agriculture
What will we learn today?
How do we classify soils?
What is a soil profile?
What is a land capability class?
What is the Soil Classification System?
Soil Profile
A soil profile is a cross-sectional view of a soil showing its many layersEach layer in the soil is called a horizonShows many characteristics of each layer:
ThicknessColorTextureStructure
Soil Horizons
A Horizon – TOPSOIL1” to 3’ deep depending on region
Rich in humus, soil organisms, plant roots
B Horizon – SUBSOILFine particles of clay, little organic matter
Water drainage and root penetration
C Horizon – PARENT MATERIALNot true soil, weathered parent material
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Other Horizons
O Horizon - ORGANIC MATTER
Plant or animal life
Organic plant residues
Decomposers
R Horizon - BEDROCK
1’ to 1,000’+
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Land Capability Class
Land capability class is productive potential of soil based on:
texture, structure, slope and depth
Class I best for agricultural production
Class VIII least useful for agriculture
Land Capability ClassClass 1 = Few limitations that restrict their use. Best for agriculture.Class 2 = Moderate limitations that reduce the choice of plants or that require
moderate conservation practices.Class 3 = Severe limitations reducing choice of plants or requiring very careful
management or both.Class 4 = Very severe limitations reducing the choice of plants or requiring very
careful management or both.Class 5 = Not likely to erode but have other limitations, impractical to remove,
that limit their use.Class 6 = Severe limitations that making them generally unsuitable for cultivation.Class 7 = Very severe limitations making them unavailable for cultivation.Class 8 = Suitable only for wildlife, forests, and recreation.
Subclasses indicate major limitations within a class. Class I has no subclasses.
Subclass E = Risk of erosion unless close-growing plant cover is maintained.Subclass W = Water in or on the soil interferes with plant growth or cultivation Subclass S = Shallow, droughty, or stone.
Soil Classification System (SCS)
Developed by USDA to categorize the different types of soils that exist
All soils broken into 12 orders, then broken down further ending with series
About 10,500 known in the United States alone
Similar to binomial nomenclature used with plants, animals, etc.
Soil Classification System (SCS)
Living Organisms
Soils
Kingdom Order
Phylum Suborder
Class Great Group
Order Subgroup
Family Family
Genus Series
Species Phase
What did we learn today?
How do we classify soils?
What is a soil profile?
What is a land capability class?
What is the Soil Classification System?