1. Soil Temperature
as applied to growing seasons
Denise Warren
What can you grow where and why???

2. What happens to the temperature of
the soil during the day?
What happens to the temperature of the soil at night?
Inquiry based lab experiment with GO Temp Data Probe to gather temperature data
Simulate Day and Night and collect data at different depths of the soil and use this
Information to understand what grows in different parts of the United States and
why it can grow there.

3. Factors that influence soil temperature
Depth
Type Rainfall/
of
of Soil Moisture
Soil
http://websoilsurvey.nrcs.usda.gov/app/Home
Page.htm
What does soil temperature influence??
Germination of Seeds
Example: Cotton needs soil
60 degrees

4. Ground Temperatures in the US
Isotherms : Lines of equal temperature as shown on this soil map at the surface

5. Excel Spreadsheet for students to
input data into for analysis

6. Materials needed for experiment
Computer, Temperature probe, plastic milk jug containing soil,
Lamp, ruler, tape and ice
Procedure
Prepare the computer for the data collection. Prepare the milk jug with soil
And three small holes, at 1 cm, 3 cm and 5 cm below the soil surface
Insert the probe into hole 1 (1cm) and record data for 20 minutes (40 for two days)
Insert the probe into hole 2 (3cm) and record data for 20 minutes
Insert the probe into hole 3 (5 cm) and record data for 20 minutes
Make sure probe is in far enough and that it is parallel to table.
Position the lamp so that the bulb is between 5 an 10 cm from soil
Fill bowl with ice
Change setup every 5 minutes. These changes will simulate the temperature
Changes over a two day period. Watch the time carefully.

7. Data Collection in experiment
Simulated Daytime, probe at 1 cm depth lamp on soil in milk carton,
data collected With GO Temp probe and recorded on laptop computer

8. Soil Temperature Data
Simulated Day/Night 40minutes total
Soil Depth 1 cm

9. Data collection in experiment:
Simulated Night time
Simulated Night time, probe at 5 cm depth ice on soil in milk
carton, data probe in soil, computer collecting data.

10. Soil temperature data at 5 cm depth
Morning Day evening night

11. Soil temperature data at 3 cm depth
Morning Day Evening Night

12. Conclusions drawn from data
Soil temperature varies the most in the first centimeter (close to the surface)
Soil temperature remains relatively constant in the 3 and 5 cm layers (at depth)
How does this relate to growing crops? What does this information tell us?
We can conclude that seeds that need higher temperatures to germinate can
Not survive in some areas because the soil at the surface does not get
warm enough for a long enough time (the growing season or number of days
It would take for the crop to grow)