2. Soil Surveys
• Soil surveys contain valuable information regarding the
distribution, uses and limitations of soil. They are available for
most counties in the United States.
• On private lands, soil surveys are made as a result of a
cooperative effort between the USDA-NRCS, the local Soil and
Water Conservation District and the Land Grant University. They
can be obtained from any of the cooperating agencies.
• They are published by the USDA-Natural Resources Conservation
Service.
3. Soil Survey Map
“32B” is a soil symbol placed on an aerial photo to
indicate a specific soil type. The text portion of a soil
survey describes soil map units like this one, and the
tables part of the soil survey provide information on its
properties and capabilities, including mechanical.
4. Soil Classification
This may be the most
difficult classification
problem in science
because of the many
factors involved.
Varied Bases for
Classification
• Parent Material
• Special Constituent
Materials
• Maturity
• Structure
• Climate & Vegetation
Multiple Objectives
• Scientific
• Genesis & Evolution
• Agricultural
• Fertility
• Most Effective Use
• Engineering
• Slope Stability
• Expansion and
Shrinkage
• Stability of Excavations
5. ABOUT SOIL TAXONOMY
• Soil Taxonomy began in the late 1960’s with a series of approximations.
• It replaced an earlier system that among other things was thought not
to have enough flexibility to be adaptable for world-wide use.
• Soil Taxonomy groups all soils among 12 orders. Each order is further
divided into sub-orders, sub-orders into great groups, great groups into
sub-groups, sub-groups into families and families into series. The soil
series is the finest taxonomic division or taxa.
• In a soil survey a soil mapping unit is composed of many different taxa (soil
series or higher). The most common of these taxa are used in the name of
the mapping unit.
7. "The 7th Approximation"
Degree of Weathering and B Horizon Development
Little Slight Moderate Large Extreme
Entisols Aridisols
Inceptisols Alfisols
Spodosols Ultisols
Mollisols Oxisols
Soils Defined by Special Constituent Materials
Andisols Volcanic Ash
Histosols Peat, Organic Matter
Vertisols “Self-Mixing” Clay Soils
Gelisols Soils on Permafrost
14. Soil Erosion and Sedimentation
• Soil erosion is the removal of soil material by:
•Water
•Wind
• We will deal mostly with water erosion as it is the
most prevalent type of erosion in New York.
15. Confusion
• Geologic erosion is a NORMAL process that occurs all
over the earth.
• Soil erosion concerns are related to the ACCELERATED
loss of soil material from farms, forests, parks, and
even urban settings.
17. Manageable?
• Geologic Erosion - in most cases cannot be prevented.
• Soil Erosion - in most cases can and should be
prevented.
18. Why Prevent Soil Erosion
• Food Productivity - soil erosion removes the most
productive layer of the soil - the TOPSOIL.
• Left unchecked, soil erosion can render an agricultural
field useless.
19. Other whys . . .
• Sedimentation in stream channels and other water
bodies causes flooding.
• Sediment in streams affects both aquatic and
terrestrial wildlife.
• Sediment has fertilizers, pesticides, and other harmful
substances attached that can pollute our drinking
water.
20. Costs
• The cost to control soil erosion or repair its damages
runs is approximately $30 billion every year - just on
agricultural land.
•Science Magazine Vol. 267, February 1995
• That money is usually taken from local, state, and/or
federal taxes paid by citizens.
21. Water v Wind
• Water erosion is most prevalent east of the
Mississippi River where annual precipitation is 30”.
• Wind erosion is most prevalent west of the
Mississippi River where rainfall amounts are
insufficient to support adequate plant growth or
where human activity destroys the existing plant
cover.
22. Erosion Forces are NOT Exclusive
• Water and wind erosion occur all over the country:
• The east is predominated by water erosion;
• The west is predominated by wind erosion.
27. Detachment
• The result of the force of the raindrop impact where
surface soil aggregates become separated or
shattered into smaller aggregates or individual soil
particles.
29. Transportation
• The process by which the detached soil particles
become suspended in water moving downhill.
• The steeper the hill, the faster the water will travel as
RUNOFF.
• The faster the water travels downhill, the greater the
amount of soil that can be held in suspension by the
water.
30. Deposition
• The process whereby the suspended soil settles out of
the running water.
• This usually occurs where the slope decreases or a
barrier exists that slows the moving water down.
• This is also know as SEDIMENTATION.
32. So, what is Soil Erosion?
• Soil erosion is the wearing away of the soil surface by
human activity that affects our ability to grow food,
causes, flooding, affects wildlife habitat, and can
pollute drinking water.
34. Types of Soil Erosion by Water
• Sheet
• Rill
• Gully
• Note: The definitions that follow are taken from:
United States Department of Agriculture. 1993. Soil Survey Manual. Agricultural
Handbook 18. Washington, D.C.
35. Sheet Erosion
• The more or less uniform removal of soil from an
area without the development of conspicuous
water channels.
• Sheet erosion is very difficult to see.
• The loss of 6 tons of soil from an acre of land
would be about the thickness of a dime across that
acre.
• Most soils in New York can only tolerate a loss of 2
to 3 tons per acre per year.
37. Rill Erosion
• The removal of soil through the cutting of many small, but
conspicuous, channels where runoff [water] concentrates.
• The channels are shallow enough that they are easily obliterated by
tillage or cultivation.
39. Gully Erosion
• The most accelerated and damaging form of water erosion that is the
consequence of water that cuts down into the soil along lines of flow.
• Gullies are characterized by a headwall that is actively being cut
uphill.
• Gullies normally cannot be crossed with common types of farm
equipment.
41. Principles of Treating Soil Erosion
• In general:
•Treat the source first, then treat the affected area.
•Practices should be cost-effective (benefits should
outweigh costs).
•Practices must be operated and maintained to
ensure they will last.
42. Agricultural Conservation Practices
• Examples of Practices To Control Soil Erosion from
Water
•Cover Crops
•Conservation Tillage
•Contour Stripcropping
•Diversions
43. Cover Crops
• Cover crops are used to help control erosion on
cropland when:
•the usual crops are not growing (fall and winter); or
•between the rows of crops such as corn, potatoes,
or tomatoes to control erosion during the growing
season.
• Cover crops also add organic matter to the soil and
improve overall soil quality.
45. Conservation Tillage
• Conservation tillage is any form of plowing that:
•Causes little or no disturbance to the soil surface;
•Helps to keep the crop residue from the previous
growing season on the soil surface to act as a
mulch.
47. Contour Stripcropping
• Contour stripcropping is a method of planting
alternating strips of land with row crops and close-
sown crops (grass for hay) that follow topography.
• The strips help to slow moving water down and allow
it to infiltrate into the soil. Many strips are about
100’in width.
49. Terrace
• A terrace is a structure that is constructed across a hillside to
intercept water moving down hill.
50. Non Agricultural Erosion Control
• Soil erosion can occur off farms as well.
• In many cases, the amount of soil lost from a
construction site exceeds that lost from an average
sized farm field in New York.
