# Presentation: 061641

## We Study Soil Because It’s A(n)

**We Study Soil Because It’s A(n)**

**Great integrator**

- Producer and
- absorber of gases (CO2 and others)

- Medium for plant growth

- Medium of crop production

- Home to organisms
- (plants, animals and others)

- Waste decomposer

*Snapshot* of geologic, climatic,
- biological, and human history

- Source material for construction,
- medicine, art, etc.

- Filter of water and wastes

- Essential natural resource

- Medium of heat and
- water storage

## Hydrologic Cycle

- Water enters the soil, interacts with soil particles and leaves the soil (through evaporation, transpiration or leaching).

## Hydrologic Cycle and the Soil

**Hydrologic Cycle and the Soil**

- Color

- Structure

- Bulk Density

- Texture

- pH

- Temperature

- Moisture

- Horizon
- Depths

- Soil Properties that are part of the hydrologic cycle.

## Soil Forming Factors

- Parent Material

- Topography

- Time

- Climate

- Biota

- Forest soil from Florida, USA

**These five factors work together to create **
**a unique soil profile made of layers called horizons.**

**For GLOBE Soil Characterization, we will describe, **
**sample and analyze the soils from horizons **
**of different soil profiles.**

## Soil Profile Comparison

- Forest soil in Florida, USA

- Forest soil in Tallinn, Estonia

- Soil profiles in different geographic regions will be similar if the five soil forming factors act on those soils the same way.

**Soil Profile Comparison**

## Soil Characterization and Moisture Protocols

- Basic
- Field Characterization
- Bulk Density
- pH
- Soil Moisture*
- Soil Temperature*
- * Taught in conjunction with Atmosphere Protocol Sessions

- Advanced
- Particle Size Distribution
- Particle Density
- Soil Fertility

- Optional
- Soil Infiltration

## Soil Characterization

- Following this protocol, you and your students will:

- 1. Expose the top 1 meter of soil
- 2. Describe the exposed soil profile
- 3. Take samples of each soil horizon
- 4. Prepare soil samples for lab analyses
- 5. Analyze the soil samples in the lab
- 6. Review the data to understand
-    your soil better
- 7. Submit the data to GLOBE

- Grassland soil

## Soil Characterization

- 1. Near the Soil Moisture study site
- 2. Within the Biology study site

- Field measurements are done
- once at each site

- Three replicate samples (and extra samples from each horizon in separate plastic bags) from each horizon are taken and reported one time for each site.

**Soil Characterization**

- Soil Sampling Sites and Strategies

## Characterization and Sampling Options

**Soil Pit**

**Auger**

**Exposed Profile (road cut)**

**Surface Sample**

- Dig a soil pit at least
- 1 meter deep and as
- big around as is
- necessary to easily
- observe all of the soil
- horizons from the
- bottom to the top of
- the pit.

- Use an auger to
- remove soil
- samples to a
- depth of 1 meter.

- Use a road cut, excavation site, or
- other location where the top 1 meter
- of soil has been exposed.

- Use a garden trowel or shovel to
- sample only the top 10 cm of soil, if
- digging to a depth of 1 meter is not
- possible.

## Soil Pit Technique

- Place golf tee or marker at the top and bottom of each horizon to clearly identify it.

- Look for: different colors, shapes, roots, the size and amount of stones, small dark nodules (called concretions), worms, or other small animals and insects, worm channels, and anything else that is noticeable.

- Soil formed under very dry or arid conditions in New Mexico, USA

**Finding and Describing Horizons**

**Soil Pit Technique**

## Exposed Profile (Road Cut) Technique

- Expose a fresh soil face by scraping approximately 2cm off of the vertical surface of the soil profile.

- Follow Soil Pit Technique directions.

**Exposed Profile (Road Cut) Technique**

**Finding and Describing Horizons**

## Soil Structure

**Horizon Properties**

**With Structure**

- Granular

- Blocky

- Prismatic

- Columnar

- Platy

**Soil Structure**

## Soil Structure

- Single Grained

- Massive

**Horizon Properties**

**Soil Structure**

**Without Structure**

- Pencil is 19 cm

- See hands for relative size

## Soil Color

**Soil Color**

**Munsell Notation**

- Hue

- Value

- Chroma

## Soil Color (continued)

- 2.	Stand with the sun over your shoulder so that sunlight shines on the color chart and the soil sample you are examining.

- 3.	Break the ped and compare the color of the inside surface with the soil color chart.

**Note: ****Sometimnes, a soil sample may have more than one color.  Record a maximum of two colors if necessary, and indicate (1) the Main (dominant color) and (2) the Other (sub-dominant color).**

**Horizon Properties**

**Soil Color (continued)**

## Soil Consistence

- Extremely Firm: The ped can’t be crushed with your fingers (you need a hammer!).

- Firm: 	The ped breaks when you apply a good amount of pressure and dents your fingers before it breaks.

- Friable:	The ped breaks with a small amount of pressure.

- * Soils with “single grained” structure **always** have loose consistence.

**Horizon Properties**

**Soil Consistence**

## Soil Texture

- ✦ Soil texture depends on the amount of each size of particle in the soil.

- ✦ Sand, silt, and clay are names that describe the size of individual particles in the soil.

- Sand are the largest particles and they feel “**gritty**.”

- Silt are medium sized, and they feel soft, silky or “**floury**.”

- Clay are the smallest sized particles, and they feel “**sticky**” and they are hard to squeeze.

**Horizon Properties**

**Soil Texture**

## Soil Texture (continued)

**Soil Texture (continued)**

**Relative Size Comparison of Soil Particles**

- Sand
- (feels gritty)

- Silt
- (feels floury)

- (2.00 - 0.05 mm, USDA)
- (2.00 - 0.02 mm, ISSS)

- (0.05 - 0.002 mm, USDA)
- (0.02 - 0.002 mm, ISSS)

- (< 0.002 mm, USDA)
- (< 0.002 mm, ISSS)

- barrel

- plate

- plate

## Soil Texture (continued)

**Step 1. Start with triangle #1**

- ✦ Test for CLAY first: If the soil is sticky, hard to squeeze, can form a long ribbon or worm without breaking, stains your hands, has a shine when rubbed, call it a CLAY **(using triangle 1)**.

- ✦ If it is like a clay but much softer and not as sticky, call it a CLAY LOAM **(using triangle 1)**.

- ✦ If it is very soft and is not like a clay at all, call it a LOAM **(using triangle 1)**.

**Horizon Properties**

**Soil Texture (continued)**

## Soil Texture (continued)

- ✦ Next try to feel for sand.  If the soil has a “gritty,” sandy feel to it, add the word  SAND (or SANDY) to the classification from triangle 1 **(see triangle 2)**.

- ✦ If you can’t feel any sand, and the soil has a smooth feel (like flour), add the word SILT (or SILTY) **(see triangle 2)**.

- ✦ Record the texture class name of your soil sample.

- ✦ If you can feel “**some**” sand, but not a lot, keep the same classification you had from triangle 1, and don’t change it.

**Horizon Properties**

**Soil Texture (continued)**

**To Determine Soil Texture**

## Test For Free Carbonates

- This test is performed by squirting vinegar on the soil.  If free carbonates are present, they will “effervesce” or bubble when the vinegar reacts with them.  Record one of the following based on your observation:

- None:	you observe no reaction (the soil has no free carbonates).

- Slight:	you observe a slight amount of bubbling (the soil is coated with some carbonates).

- Strong:	you observe a strong reaction (many bubbles) (the soil has many carbonate coatings present).

**Horizon Properties**

**Test For Free Carbonates**

## Preparing for the Field

- 1.	Fill acid bottle with vinegar
- 2.	Fill squirt bottles with water
- 3.	Make a clinometer (see Land
- 	Cover/Biology Protocol)
- 4.	Collect bulk density containers
- 		a.	find can mass
- 		b.	find can volume by filling 		the can with water, pouring 		the water into a graduated 		cylinder, and reading the 		amount in mL.
- 		c.	label cans
- 		d.	hammer hole in bottom

- Note: If using the auger sampling method, take bulk density samples at the surface of the soil as per the Bulk Density protocol for the Surface Sample technique.