Soil Tests Help Manage Soil
FOR IMMEDIATE RELEASE
September 6, 2013
Ill. - Soil tests are one tool in your toolbox for managing landscape soil,
said a University of Illinois Extension horticulture educator.
good soil structure and soil moisture are of first importance," said Nancy
Pollard. "You can improve or maintain soil structure by working the soil only
when it is not wet and by incorporating organic matter into the soil on an
added that applying mulches, watering as needed, and improving drainage where
feasible will help with moisture control in soil. Soil testing and
applying fertilizers accordingly are additional steps in effective soil
well-taken soil test will help in making management decisions. "It will
help answer questions like, 'Is there already enough phosphorus and potassium
in the soil? Is it desirable to go to the expense to add more? Does
the pH (acidity) of my soil match the requirements of the plants I want to
grow?'" she said.
are pH, phosphorus (P), and potassium (K) levels, and sometimes magnesium (Mg)
and Calcium (Ca). Usually estimated percent organic matter, and Cation
Exchange Capacity (CEC) are shown in the results as well, Pollard
explained. "Although high CEC soils can hold more nutrients, it doesn't
necessarily imply that they are more productive. Much depends on good soil
management. Adding good organic matter always helps," she said.
do not test for nitrogen (N) because it is unstable in soil. If there is a
recommendation for nitrogen, it is a standard one assumed for that particular
only make recommendations if you include the name of the crop you are growing
such as apples, blueberries, turf grass, perennials, tomatoes, or a general
vegetable garden," she explained. "Also, state that it is a home garden or your
recommendations will be in tons per acre instead of pounds per 1,000 square
labs are listed at http://urbanext.illinois.edu/soiltest/ or can be obtained by
calling a U of I Extension office for a copy of those listed. Pollard said
after obtaining the list growers should call for current fees and services.
"Request an interpretation of the soil test results. Often labs will provide
sample bags prior to you taking a soil sample if you request sampling
information. Look for labs that give interpretations for home gardens," she
"Recommendations can be no better than the sample tested," Pollard
said. "You will need to create a composite sample from the yard or garden
area you want to know about so the results aren't skewed to one spot."
To create a sample, within the area selected, dig a hole to spade
depth. With a shovel or trowel, cut a thin slice down one side of the hole.
Place this slice in a clean pail. Do not include sod roots. Repeat this
procedure in at least eight well-scattered spots within the chosen area. Place
each slice in the pail with those previously taken. Break up clods and mix the
slices of soil thoroughly, rotating the pail while mixing.
"In the end, you will only need to send about a
representative cup or pint, the amount requested by the lab. Be ready to label
the sample with your name and address and the crop," she said. "If you are
sending more than one, label each sample with a number, which will tell you
where the sample was taken. Mark the sample flower garden, vegetable garden,
shrub border, or lawn, etc. The more complete the information provided, the
better the management recommendations will be."
Heavy metal tests are additional tests that can be done. Pollard
said to test for lead (Pb) if the food garden or children's garden is within
1,500 feet of a highway that had busy traffic prior to 1970. "That is when gas
contained lead. Also test for lead if the property was built before 1950 and
paint chips may be contaminating the soil. Lead was banned from use in interior
and exterior house paint in 1978," she said.
"Other tests include testing for arsenic if an old orchard was on
site. Arsenic was formerly used as an orchard pesticide. Knowing the
history of your land can give you clues of possible other metals or compounds
to test for," she added.
Separate tests are required for each metal or compound.
"There is no one-size-fits-all test like it might appear on television.
That is why knowing the history of your site is useful in determining if there
are risks you want or need to evaluate. Soil tests are one tool in your toolbox
for learning about and managing your soil," Pollard said.
Source: Nancy Pollard, Extension Educator, Horticulture, firstname.lastname@example.org