Initial Soil Collection
- Students will obtain soil samples directly on the KCKCC
campus (weather permitting). Allow
students a good 20 minutes to leave, collect, bring back, and label…and/or find
their EXACT location via a computer.
- Instructors will receive baggies with labels – and a set of
‘mini-instructions’ inside. The students
will be ‘instructed’ to collect a small soil sample from a near-by area of
- The students will use a small, metal implement or plastic
spoon to ‘dig up’ their small soil sample (the sample only needs to fill bag
1/5th to 1/4th full (SMALL amount).
- Once the soil is collected, the students will write the
following information on the label:
location (Kansas City, KS – KCKCC campus; longitude/latitude from
phone/gps device or from computer search; name(s); general color/texture of
- The sample will be sealed up in the baggie and brought back
to their lab station (one of the chemistry rooms).
Soil Tests from Samples Collected:
- Bacterial & Fungal Culture of Soil Sample
- Weigh out 1g of soil sample and place it in a test tube.
- Add sterile water just above the soil ‘mark’.
- Shake vigorously for 1 minute to disperse the microbes.
- Mix by inverting the tube several times.
- With the lab grease-pens, label the plates on the bottom
with your initials and date. Leave
these for Ms. Liz to incubate and photograph (we cannot ‘hold’ these over break
– but results will be provided to student groups).
- Add 0.5 ml of your dilution mix to one agar plate. Use
a sterile Q-tip to spread across the plate.
- Plate results can be viewed during the next session.
1. Place some dried soil (about 10ml-50ml…based on what is available) in a
small beaker. Tamp the soil down gently, but do not compress it.
2. Fill a small graduated cylinder with about 5-25ml (depending on amount of
soil used – amt. of soil, then ½ amt. of water) of water. Slowly pour the water onto the surface of the
soil until the soil is completely saturated and water just starts to pool up on
the surface. Add the water slowly enough to give the water a chance to
percolate down into the pores.
3. Measure the amount of water left in the graduated cylinder. The amount used
is the amount of pore space in your sample. Record volume of soil and volume of
4. Calculate porosity as a percent: % = (volume water added/10ml of soil) x
100. (IF MORE than 10ml of soil was
used, replace that value with appropriate value)
5. Based on the texture and porosity data and the following tables, determine
the relative permeability, water infiltration capacity, water holding capacity,
nutrient holding capacity, percolation, aeration, and workability of the soil
(avg permeability tables avail via web – but can be printed out)
Soil color is an indication of the amount of organic material present. Dark
brown and black soils contain a high amount of organic matter. Brown to
yellow-brown denotes a moderate amount of organic material, and pale brown to
yellow denotes a low organic content. White colors indicate the presence of
salts or carbonates, mottled colors indicate poor aeration, and blue, gray or
green tingled soils indicate that the soil is water logged.
1. Identify the color and relative organic content of your soil sample. What
does the soil smell like?
2. Why is it important to have organic material in the soil?
Soil Fertility (one
or some of these MIGHT be used – depending on availability of ‘kits’)
Soil fertility characterizes the ability of the soil to support plant growth.
In order to grow, plants require sunlight, water and essential minerals
obtained from the soil. These minerals include N, P, K, Ca, Mg, S, Cl, Fe, Mn,
Cu, Zn, Mb and B. Of these minerals, the 3 primary nutrients required by plants
are N, P and K.
There are 4 main factors that determine soil fertility: pH, the amount of
nitrogen, the amount of phosphorous, and the amount of potassium. Acidic soils
typically have lower fertility than basic soils because H+ ions in the acid
displace the positively charged nutrient ions. These nutrients can then be
leached from the soil into the groundwater. Normal pH for soil is between pH 4
- 8, but the uptake of N, P and K occurs more readily if the pH is between pH
5.5 - 7.5. Optimum soil pH varies for different types of plants. In acidic
soils (less than pH 5), plants are more likely to uptake toxic metals, such as
aluminum, iron and manganese that can kill the plants. In acidic soils, applied
pesticides, herbicides and fungicides will not be absorbed or held in the soil,
but will have a tendency to either runoff the land with rain water or percolate
into the groundwater.
Nitrates are usually stored in the soil in the organic matter. Normal levels
are between 60 -175ppm. Nitrates do not bind to soil particles and thus can
easily be leached from the soil into the groundwater, especially during heavy
rain. Phosphates in soils tend to cling to the surface of clay particles and
organic matter, and are quickly absorbed by plants. High levels of phosphates
can accumulate in the top layers of soil in the form of insoluble calcium
phosphate, and subsequently can runoff into surface water producing phosphate
rich sediments. Normal levels are between 5 - 15ppm. Normal potassium levels
are between 75 - 200ppm.
Instructions accompany each kit and are easy to follow.
1. Use the soil kits to test the pH, nitrogen, phosphorous and the potassium
content of your soil sample. Record results.
2. Is the pH within the normal range?
3. What could you add to a soil that is too acidic? To a soil that is too
basic? (Be specific)
4. Are any of the nutrients deficient in your sample? How could you increase
the fertility of the soil and at the same time build the topsoil layer and
quantity of humus?
Pollutants in the Soil
The motion of water and pollutants through soil is heavily influenced by the
properties of the soil itself. Certain soils are very likely to trap and retain
pollutants over long periods of time, while others provide for a great deal of
vertical motion for both water and pollutants.
1. Cut the neck off of two water bottles. Invert the neck in the bottles to act as
funnels. Plug the necks with a piece of
2. Fill the necks of two bottles with the soil sample to 1 cm from the top.
3. Add 20 ml methylene blue solution to one of the soil bottles until it just
begins to pool at the surface.
4. Let the soil sit until the dye drains through to the bottom of the bottle.
5. Repeat steps 3 and 4 with the remaining bottle using an eosin y solution.
6. Record the volume and color of each filtrate.
7. Is the filtrate color lighter than the beginning color? Does it appear that
the dye was filtered out by the soil?
8. Which dye was retained by the soil? Explain why one dye was retained and why
one dye moved through the soil. (Hint: one dye is cationic or positively
charged and the other dye is anionic or negatively charged.)
9. What would happen to nitrates (negatively charged anions) in these soils?
Would they be absorbed to the soil particles or have the tendency to leach into
10. How would this demonstration relate to potential pollution of groundwater
if excess nitrate fertilizers were applied to the land?
11. Considering what you have learned in this activity, what potential
remediation qualities do soils have to buffer against chemical pollution and to
act as filters for water percolating through the soil?