ED-STEEP: Education Solutions to Environmental
and Economic Problems
Collecting and Preparing Soil and Litter Samples
Choosing a Sample Site
Two or more contrasting habitats should be chosen so students can compare different kinds of
soils. Examples of different habitats with interesting soils include: coniferous forests, deciduous
forests, old fields, tilled cropland, no-till cropland, sandy soils, garden soils, compost, riparian
habitats, and grasslands. The best time to collect soils are late spring and early fall when the
weather is warm and the ground moist. In general, the greater the amount of live material falling
on the soil surface and undergoing decomposition, the greater the soil organic matter, soil
microorganisms, and soil invertebrates. Sample sites within habitats should be chosen randomly,
but the sample sites should be representative of the habitat.
Ideally, three or more sample sites per habitat should be used to give a composite sample that is
representative of the habitat. The actual number of samples will depend on the number of
students or student-groups conducting the experiment.
Note: If the purpose is to compare habitats, then true replication would involve sampling several
different locations with the same habitat (e.g., 3 grassland sites). Sampling several sites within a
single habitat is called pseudo-replication. This could be ignored for most teaching purposes.
Example of soil and litter samples collected in 2004 by a high school biology class at
Paradise Creek Regional High School, Latah County, Idaho.
Collector’s
Habitat
Name
Sample
Description of Litter
Forest
Student Group A
1
abundant pine needles and leaves
Riparian
Student Group B
2
high biomass, wet
Compost Student Group C
3
decomposed
Grassland Student Group D
4
sparse litter – lots of standing grass
Collecting Soil and Litter Samples
Soil samples can be collected ahead of time by the teacher, or can be collected by students if
different habitats are readily available. Samples should be standardized by area or volume
collected so habitat comparisons can be made. I prefer to use a 10-cm diameter golf-hole cutter
to take soil cores. Generally, a 0.1-m2 area is suitable for most soil samples. The best samples
will include litter and some soil just below the litter. Soil samples should be chosen randomly.
If students collect samples themselves, they can experiment with how to collect samples (e.g.,
walk along a transect and sample at a specific interval, throw a Frisbee with eyes closed to mark
the sample site).
Remove any standing live plants and very coarse litter. If the objective is to extract soil
invertebrates with Berlese funnels, save the coarse plant material to place in the bottom of the
funnel. Remove the soil with a shovel, trowel, or a soil corer. Samples can be placed in plastic
baggies and stored in a cool place until used. Always label everything with date, collector,
habitat, replicate number, and contents.
Materials
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ruler or quadrat for standardizing soil sample area
quart/gallon size plastic bags (2 per sample; one for litter and one for soil)
marker
trowel, shovel, or soil corer
refrigerator or cool place for storing samples
Methods
1. Measure out the 0.1-m2 area with a ruler or quadrat to standardized the sample area (this
area is suitable for most activities and will provide numerous soil invertebrates).
2. Remove any large pieces of undecomposed litter and place in a bag; label with the date,
contents, and habitat (students can sort through and describe the litter).
3. Use a trowel or shovel to remove all litter (organic material that is still identifiable) and
about 2.5 cm (1 inch) of soil under the litter – place in a bag and label.
4. Store soil/litter samples in a refrigerator or cool place until processed (for up to 24 hours)
Questions
1.
2.
3.
4.
Why are samples chosen randomly?
What are replicates and how many are needed?
What organisms are responsible for breaking down the course litter?
Describe the process of decomposition.