Introduction to Soils and

Ecological Sites

Presented by: Sarah LamagnaEcologist, NOC

Why gather soils info?

1953 1956 2010

We’re monitoring change over time

Soils help us understand landscape change

Soils help differentiate ecological sites

Ecological Sites

A kind of land, defined by its soils, topography and climate that:

1) potentially produces similar kinds and amounts of vegetation

2) responds to disturbances and drivers similarly (e.g., grazing and rainfall)

So what are the steps in identifying ecological sites?

1. Gather information in office

• Key to Ecological Sites• Topographical Map

• Soil Map• Soil Map Unit Descriptions

• Ecological Site Descriptions (ESD’s)• Climate information

Web Soil Survey

Ecological Site Descriptions

• Based on soil map units

• Each soil map unit matches up with one or more ecological sites

2. Go to the field

• Navigate to your site.• Find out where you are on the maps.

• According to the soil map units in the area, what ecological site(s) could you be on?

3. Compare physical characteristics – DIG A PIT!

• Do you have the same topography as the ESD?• Are you at the same elevation as the ESD?

• Are the soil properties (esp. texture) the same as described in the soil map unit component and

associated ESD?

4. Compare vegetation

• What plants are on the site?• Which state or community are you in?

What exactly goes in to digging a soil pit?

A soil scientist helps!!!

Bulk Density

Structure

Color

What soil properties does AIM require you to measure?

Texture

Soil Horizon Depth

Effervescence

Coarse Fragments

Percent Clay

Structure

Color

Bulk Density

Soil Profile Data Sheet

Part of Plot Characterization Data Sheet

Match each soil property with its corresponding reason for collecting it

Texture

Horizon Depth

Effervescence

Coarse Fragments

Percent Clay

Affects all soil processes and one of the most important soil properties

Indicator of calcium carbonate content

Important in understanding the processes of water infiltration and availability, soil stability/erodibility, and plant rooting

Affects soil water availability through infiltration, storage, and evaporation

Describes entire soil ped to help determine ecological site ID

Color

Structure

Affects soil water availability through depth that water can penetrate and residence time that water is available to plants

Indicator of the amount of organic matter which is important for water holding capacity and nutrient availability

How many horizons do you see?

What are the differences in soil

properties between horizons?

How many horizons do you see in each soil pit?

Sandy Site Loamy Site

How many horizons do you see in each soil pit?

Sandy Site Loamy Site

Sandy Site Loamy Site

What differences in soil properties can you see?

What differences in soil properties can you see?

Sandy ClayLoam

SandyLoam

Sandy Clay Loam

Calcic w/ ~20% CaCO3

LoamySand

Fine Sandy Loam

Sandy Site Loamy Site

Calcic

Petro-calcic

How many horizons do you see in each soil pit?

How many horizons do you see in each soil pit?

What differences in soil properties can you see?

What differences in soil properties can you see?

LoamySand

Calcic w/ ~20% CaCO3

Sandy Loam

Silty ClayLoam

Silt Loam

LoamySand

LoamySand

LoamySand

Soil profiles common to Oregon

A horizon -High OM

Clayey

Welded tuffCompaction

VERYCommon

Soil profiles common to Oregon

Ash

Vertic Clay

Vertic ClayWeaker Structure

Welded Tuff

VERYCommon

Soil profiles common to Oregon

Ash

Vertic Clay –High Rock Fragment %

Welded Tuff

VERYCommon

Soil profiles common to Oregon

Ash

Vertic Clay

Vertic Clay –Color change

Soil Texture Flowchart

Soil and ecological site resources

• Web Soil Survey

• SoilWeb App for iPhone and Android

• Soil Series Descriptions

• List of Published Soil Surveys

• Approved Ecological Site Descriptions

• LandPKS App for Site Characterization

For more soil background info:

Field Book for Describing and Sampling Soils –plus video on how to use it

Factors of Soil Formation – classic book by Hans Jenny available online

The Nature and Properties of Soils – book to purchase that provides a clearly written, general overview

Soils: Genesis and Geomorphology – textbook to purchase

Getting your hands dirty will help!

Questions?