Guide, part 1: Soil Characterization
Soil Characterization Protocols
A Step by Step Guide Field Analysis
- Great integrator
- Medium of crop production
- Filter of water and wastes
- Producer and absorber of gases
- Home to organisms (plants, animals and others)
- Medium for plant growth
- Snapshot of geologic, climatic, biological, and human history
- Source material for construction, medicine, art, etc.
- Essential natural resource
- Waste decomposer
- Parent Material
- (The first four factors over) Time
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.
Following this protocol, you and your students will:
- expose the top 1 meter of soil
- describe the exposed soil profile
- take samples of each soil horizon
- prepare soil samples for lab analyses
- analyze the soil samples in the lab
- review the data to understand your soil better
- submit the data to GLOBE
Sample at least two sites.
|1. Near the Soil Moisture study site||2. Within the Biology study site|
Field measurements are done once at each site
Three replicate samples from each horizon are taken and reported one time for each site.
Characterization and Sampling Options
|Soil Pit||Exposed Profile (road cut)|
|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 a road cut, excavation site, or other location where the top 1 meter of soil has been exposed.
Use an auger to remove soil samples to a depth of 1 meter.
Instruments for Field Analysis
Digging pit or hole
Shovel or Auger Trowels
Laying out profile
Plastic Tarp or Trash Bag
Nails, Golf Tees, or other tool for marking horizon boundary marker
Measuring depth of profile
Moistening profile face
Instruments for Field Analysis 2
Instruments for conducting Bulk Density and field protocols
Soil sampling for lab protocols
4 Liter (1 Gallon) size Ziplock Bags or Containers
Sampling Cans Wood Block and Hammer
Soil Color Book
Free Carbonate test
Vinegar in acid bottle
Study site slope
Clinometer (You may use the clinometer that you made for the Land cover/Biology protocol.)
Instruments for recording data about soil profile
Field protocol information
Soil Characterization Information Sheet
Soil Characterization and Bulk Density Data Entry Sheets Water Proof Marker and Pencils
Soil Profile photograph
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
For Pit, Exposed Profile, and Surface Sample Method
a. find can weight
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
For Auger Method
a. label the containers
Finding and Describing Horizons
First, obtain permission to dig a pit. Obey any and all safety precautions requested, and ask about power and water lines.
- Starting from top, observe profile to determine properties and differences between horizons.
- 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.
Arid climate soil in New Mexico, USA
Forest soil in Florida, USA
First, obtain permission to take samples from the road cut, excavation, or other soil profile exposed by others. Obey any and all safety precautions requested. Ask about power and water lines.
Expose a fresh soil face.
Follow Soil Pit Technique directions.
1. Identify an area where you can dig four holes where the soil profiles should be similar.
2. Spread a plastic bag, tarp, board, or other surface on the ground next to where you will dig your first hole.
3. Assemble a profile of the top 1 meter of the soil by removing successive samples with the auger and laying them end-to-end as follows:
4. Identify each horizon and measure its thickness using the depth of the auger hole.
In situations where it is not possible to expose the top meter of soil, another option is to use the top 10 cm of soil as a horizon sample for soil characterization.