Earthworks
Earth System Science for Secondary Teachers

Kathryn Grohusky (Earthworks 2001)
kathryndg@keystone.org

A Proposal to add Soil Science to the KSS Curriculum
Soil Science for 4^th - 12^th grade students at Keystone Science School, CO

Rationale: The purpose of investigating the potential to conduct soil analysis as part of KSS program offerings is to increase our research capabilities and expertise into a new topic area. This proposal if accepted would allow us to offer our clients the opportunity to analyze the physical and chemical characteristics of soil in our county during their visit to KSS. In addition, providing training during their visit would allow teachers to conduct their own analysis back at home for comparison. Physical and chemical soil characteristics are known indicators of soil genesis and soil development. There are a variety of reasons to add soil analysis to our curriculum. These include investigating the effects of recreation on soils, the effects of altitude on soil development, the effects of development (housing and retail) on soils, and the interrelationships between vegetation, snow, animals and soil. We currently do not have a soil analysis program in place. This curriculum would greatly increase our ability to offer cutting edge Earth Science programs and research projects. Soil research would allow us to help teachers meet ES standards.

Overview: Soils differ in their development depending on five influences (factors): Time, Parent Material (Geology), Vegetation, Topography, and Climate. Many Environemtnal Issues influense soil or are influenced by soil.

Possibilities for Research Questions: ADD MORE as questions are developed.

The soils of a biosequence differ primarily with respect to biota (vegetation); the other soil-forming influences (factors) are held relatively constant. Note: The four additional soil sequences include: chronosequence (variation by time); lithosequence (variation by geologic parent material); toposequence (variation by topography); and climosequence (variation by climate).

Vocabulary List

Ped
Soil
Biosequence ADD MORE HERE!
Slope
Slope Position
Aspect
Grade

Potential Variables to Analyze include:

a)      Site descriptions, Landmarks
b)      Major Vegetative Species
c)      Time and Date
d)      Latitude, Longitude, Altitude
e)      Weather
f)        Grade/Slope, Aspect, Slope Position
g)      Identify Characteristics of each Horizon:

i)        General "First Impressions";
ii)       Horizon Name (Type of Horizon),
iii)     Thickness,
iv)     Dry Color,
v)      Moist Color,
vi)     Texture,
vii)   Structure,
viii)  Nitrogen,
ix)     Phosphorous,
x)      Potassium,
xi)     pH,
xii)   Particle Size (Sand, Silt, Clay), Texture

Soil Sample Data Collection Sheet

Soil ScienceConcepts for Instructors -

Nitrates and Nitrites:

More nitrates are expected in the A Horizon of wetland sample sites due to the high amount of biota and organic matter. In some cases the nitrogen is in the form of nitrites, bound up in the soil, and can not be measured with nitrate analysis equipment.

Minerals from Parent Materials - An Example from Cal-Wood case study:

The potassium levels were high in each horizon. In fact, the concentrations were higher than the range tested in the HACH Soil Analysis Kit ( 87 - 294 mg/L). Therefore our sample concentrations were extrapolated and found to be in the range of 360 - 441 mg/L. The granite bedrock in this area has a large quantity of potassium feldspar. As this local granite weathers, the potassium feldspar decomposes into free potassium in the soil. There are many types of parent material that can create this type of high concentration in soil. What are the relevant minerals in Summit County?

Look for color differences and correlate them to differences in soil characteristics:

A) Most of the organic material in a conifer forest is on top of the soils and not incorporated by fine roots into the soil itself. The layers of organic material are the O horizons and are not considered soil. The A and E horizons can be very different in their color. The reason these two layers can be so different in color is the difference in the amounts of organic materials. The organic material in conifer forest soil is located for the most part in the A horizon. This is due in part to the coarser roots of conifers. The coarse roots break down bedrock into soils very slowly (in comparison to fine grass roots that penetrate and break up dense soils allowing them to further decompose.) Typically, only shallow thicknesses of soil are present in conifer forest. In addition, steeper slopes discourage the accumulation of organic matter due to erosion.

B)The different colors of the A horizons of grassland ( light brown color similar to a latte) and wetland ( a very dark brown similar to a dark chocolate, almost black) are due to the amounts of organic material . A grassland A horizon, located on an open south-east aspect receives more sun than a wetland area. The sun dries the soil and reduces decomposition. The wetland toe slope also serves to increase accumulation of organic matter.

Soil Depth:

The depth of A horizons vary along a biosequence. (see case study) This variation is due in part to factors as described above in the discussion of color differences (darker colors indicate more organic material). The accumulation of organic material is a major determinant of the thickness of soil. The wetland sample site, the thickest A horizon (40 cm), is in a depositional area. The other three thinner samples were collected from erosional areas. There is less root death in the conifer and grassland sample sites (thinner A horizons) and more in the aspen and grassland areas (thicker A horizons). The grasses evaporate water into the air more than other vegetation, increasing the dryness of the soil and thus decreasing decomposition.

Resources

Kathryn Davis Grohusky - Participated in Earthworks, July 2001 - learned a great deal about soils in general, how to analyze, ideas for implementation.
Soil Science Specialists and Project ConsultantsDepartment of Soil & Crop Science. Colorado State University, Fort Collins, CO.
Grant Cardon, Gene Kelly, Caroline Yonker. Caroline could provide training for staff - Call her!

Other teachers experienced in these procedures: (see contact list for info)
Steve - Cal-Wood Program Director, Cal Wood, Jamestown, CO.
Sue Anne Berger - Colorado. School of Mines
Nancy Gettman - Woodlin School, CO
Kathryn Grohusky - Keystone Science School, CO
Gary Popiolkowski - Chartiers-Houston School, PA,

HACH. The Analytical Methods Company. "NPK-1 Soil Kit Manual." Loveland, CO.
LaMOTTE Company. "Soil Texture Unit." Chestertown, Maryland.

References

Boulding, J. Russell. Description and Sampling of Contaminated Soils. A Field Guild.
Ann Arbor: Lewis Publishing Co, 1994.

Carter, Martin R. Soil Sampling and Methods of Analysis. Ann Arbor: Lewis Publishing
Co., 1993.

Miller, Raymond and Roy Donahue. Soils. An Introduction to Soils and Plant Growth.
Englewood Cliffs: Prentice Hall, 1990.

Pierzynski, Gary, Thomas Simes, George Vance. Soils and Environmental Quality. Ann
Arbor: Lewis Publishing Co., 1994.

Lesson Extension and Connection Ideas

Life Sciences Connection: Compare diversity and number of organisms in A Horizon Samples

Materials:

Funnels (1 for each sample), Funnel Racks or Supports (can be home-made), Heat/Light Source (Lamp), Petri Dish (1 for each sample), Dissecting Microscope, Identification Keys for Invertebrates, Cheese Cloth

Procedures

Set-up funnels and light/heat source station: Figure #1; Place a labeled petri dish directly under each of the funnel locations; Fill each of the petri dishes half full of water; Cut cheese cloth into 8" squares, 4 layers thick, one for each funnel; Place cheesecloth in each funnel and press downward to form a well; Holding the funnel with the cheesecloth over a trash can pour 100ml of soil into it; Carefully place the funnel into the funnel support directly over the correctly labeled petri dish; Turn on the lamps making sure the lights are centered over the samples; Leave on for a minimum of 6 hours and up to 24 hours. Check often, and don't allow the samples to become to hot; Turn off lamp; remove funnel setup, and place soil back into appropriate sample bag; Set-up dissecting microscope, get references and identification keys, move sample petri dish for observation and identifications; Identify individual organisms; Talley number of organisms; Compare data to soil sample variations between sites.