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Soil and Site Evaluation

Getting the Dirt on SoilsBy

Dr. David Lindbo, NCSUCooperate Extension

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Acknowledgement

This work was supported [in part] by the National Decentralized Water Resources Capacity Development Project with funding

provided by the U.S. Environmental Protection Agency through a Cooperative Agreement (EPA No. CR827881-01-0) with

Washington University in St. Louis. The results have not been reviewed by EPA or Washington University in St. Louis. The

views expressed in this presentation are solely those of NCSU, and University of Arkansas and EPA and Washington University in St.

Louis do not endorse any products or commercial services mentioned in the presentation.

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What are 4 things we cannot live

without?

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AIR

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SUNLIGHT

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WATER

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SOIL

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Does Soil=

Dirt?

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Dirt is the stuff under your fingernails or what you sweep off the floor

NO

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Soil FactsTopsoil is the most productive layer

Five tons of topsoil spread over an acre is only as thick as a dime

Soil supplies water and nutrients for plants

Most of our food comes from soil

It can take more than 500 years to form one inch of topsoil

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Soil FactsAn acre of corn gives off 4000 gallons of water a day in evaporation

Soil Scientist have identified over 70,000 different soils in the U. S.

Erosion of soil clogs rivers and lakes

Soil influences the life spans of roads

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Soil FactsSoil is alive….

1 gram of soil contains up to a billion bacteria

There many thousands of types of bacteria in soil

15 tons of soil per acre pass through earthworms each year

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Soil FactsSoil is the largest single wastewater treatment unit in North Carolina

3.5 million North Carolinians rely on soil to treat and disperse wastewater

Soil is extremely effective at wastewater treatment

Best of all…

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Soil makes great mud pies

…and is just plain fun!

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What is a soil?And why do we care?

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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A soil is a porous natural body of

mineral, air, water and organic matter that changes, or has

changed, in response to climate, topography, time, and organisms.

This is the text book definition. Basically, it says that soils are dynamic and reflect the conditions that they formed under. Because they do reflect the environment in which they formed we can use their morphology to understand more about the environment. Thus soils can be like a very smart canary in the coal mine – if we know how to interpret their song.

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Soil Science Society of America

soil: (i) the unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants.

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Rule .1935 (41) Soil

“Soil” means the naturally occurring body of porous mineral and organic materials on the land surface. Soil is composed of sand-, silt-and clay-sized particles that are mixed with varying amounts of larger fragments and some organic material. Soil contains less than 50% of its volume as rock, saprolite, or coarse-earth fraction (mineral particle greater than 2 mm). The upper limit of the soil is the land surface, and its lower limit is “rock”, saprolite, or other parent materials.

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Soil Definition

“Soil” means the naturally occurring body

of porous mineral and organic

materials on the land surface.

The upper limit of the soil is the land surface, and its lower limit is “rock”.

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What is a soil?And why do we care?

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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Importance of Soil to On-site Wastewater

Biological treatmentChemical treatmentPhysical treatmentDispersal

Just as in a wastewater treatment plant soils treat the wastewater I much the same way.

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How does soil treat wastewater?

Groundwater

Well

Aerobic soil

Aerobic soil is needed to treat – remove pathogens – and disperse the treated wastewater back into the environment

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What is a soil?And why do we care?

What is a soil? What does it mean to you? Does it have and special meaning to you? Before answering these questions consider what you see in the soil.

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What is soil made of?

Soil is composed of minerals,

organic matter, air,

water

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Soil is made of:

Solid materialMineralsDead organic materialLiving organic material

Pore spaceAirWater

Soil has two major components that can be subdivide into 5 five components overall. Their relative amounts will alter the properties of the soil but no one is more important than another.

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What does the site evaluator need to

know?

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Next lecturesParent MaterialTopographySoil Texture Soil StructureSoil Consistence

Soil Color Profile DescriptionSite EvaluationDetermination of LTARSoil Survey

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Summary

Soils are the living skin of the earthSoils treat wastewaterSoils are complex

SOILS SUSTAIN LIFE