Soil Temperature

Step 3: Soil Temperature

Materials

LabQuest2
Soil Temperature Probe
Ruler/Measuring Tape
Wash Bottle w/ Distilled Water
Sheets of Paper/Plastic/Cloth (to put soil on temporarily)
Hand Shovel
Paper Towels

To measure soil temperatures at your plots, you will be using a traditional soil thermometer and recording the readings manually on a pre-created table in LabQuest2.  Soil temperature is an important factor which determines the location of JB grubs (see an illustration of the JB life cycle at www.usda.gov).

Soil thermometer

Soil thermometer in action: Photo courtesy of Kohen Joiner, ENVS student, ESC

Methods:  Recording Soil Temperature Data Manually in LabQuest2
A data table has been provided below for those needing to record their temperature data in a paper table.

--To access the soil temperature table, tap on “File” (top of screen) and highlight open.  From the file list, highlight Soil Temperatures and open the file.                                                                              

--Before you begin collecting your soil temperature data, save your own version of the table.  Tap on “File,” highlight “Save,” and tap on the title window.  A keypad will pop up and you can title your file: firstinitiallastnamesoiltemperatures (e.g. ljonessoiltemperatures).  Tap on “Done” and “Save.”

--After taking a soil temperature reading, tap on the cell in the table which corresponds to the depth, plot, and sample point at which you took the temperature reading.  Enter the temperature (OC) in the cell.

Note: If you have difficulty accessing or creating a table on the LabQuest2 unit, you can record your data on a data collection sheet that you create. 

 

Methods:  Soil Temperature

You will be taking soil temperatures at the 3 random sample points you mark in each of your plots.  Before moving on to soil moisture, complete soil temperature sampling at each sample point in the plot in which you are currently working.

--Gently, insert the soil temperature probe 5 cm into the soil.  When the temperature reading stabilizes (the needle on the thermometer remains stationary for ~10 sec.) record the reading in your Soil Temperature table in LabQuest2.  Length of the probe above the soil = 16.5 cm.**

--Remove the probe and wipe clean with a damp paper towel.

--Gently, push the soil temperature probe further into the soil to a depth of 10 cm.  When the temperature reading stabilizes (the needle on the thermometer remains stationary for ~10 sec.) record the reading in your Soil Temperature table in LabQuest2.  Length of the probe above the soil = 11.5 cm.**

--Remove the probe and wipe clean with a damp paper towel.

**Point of reference—the soil temperature probe, from the top of the glass to the point, is 21.5 cm in length.

Because the soil temperature probe is only 21.5 cm in length, you will need to widen your sample point a bit to determine temperatures at 20 cm and 30 cm.  Store the probe in its storage box while you further deepen the hole.

--Place sheets of paper/plastic/cloth next to your sample point.  Dig a narrow square to a depth of 5 cm and place soil in one pile on the sheets.  Do not make the opening wider than 15 cm x 15 cm. 

--Continue digging to a depth of 10 cm and place the soil from 5 cm—10 cm in another pile on the sheets. 

Tip:     Excavate your sample point in layers, creating a 15 cm x 15 cm hole to access the 20 cm and 30 cm depths for your temperature measurements.  When you collect your soil moisture data, you will need a wider hole to accommodate the soil moisture sensor. 

Note:   Do not make your holes larger than 15 cm x 15 cm.  When you collect your JB data, you will be recording the % soil coverage of JB eggs and/or counting the number grubs you observe in 15 cm x 15 cm x depth layers at each of your plot sample points.

Note:   If you hit bedrock or other parent material before reaching the 30 cm depth, go no deeper.  Record the deepest depth at which you are able to gather data and note the reason.

--Gently, insert the probe 10 cm into the hole, to a depth of 20 cm (length of the probe above the soil = 11.5 cm).  When the temperature reading stabilizes (the needle on the thermometer remains stationary) record the reading in your Soil Temperature table in LabQuest2. 

--Remove the probe and wipe clean with a damp paper towel.  Store the probe in its storage box while you further deepen the hole.

--Continue digging to a depth of 20 cm and place the soil from 10 cm—20 cm in another pile on the sheets. 

--Gently, insert the probe 10 cm into the hole, to a depth of 30 cm (length of the probe above the soil = 11.5 cm).  When the temperature reading stabilizes (the needle on the thermometer remains stationary for ~10 sec.) record the reading in your Soil Temperature table in LabQuest2. 

--Remove the probe and wipe clean with a damp paper towel.  Store the probe in its storage box while you move to the next sampling point in your plot.

--Save your file before moving to your next sample point.  Tap on “File,” highlight “Save,” and highlight the name of your soil temperature file.  Tap “Save” and “Overwrite.”

--Repeat the sampling method at each of your sample points in the plot you are currently in. 

You can use the following table to record your observations (in addition to saving data to the LabQuest 2 Unit).

Table 1: Soil temperature data from XXXXX (your site name).

Sample

Soil Temperature

5 cm (OC)

Soil Temperature

10 cm (OC)

Soil Temperature

20 cm (OC)

Soil Temperature

30 cm (OC)

Plot 1.1

 

 

 

 

Plot 1.2

 

 

 

 

Plot 1.3

 

 

 

 

Plot 1 Average

 

 

 

 

 

 

 

 

 

Plot 2.1

 

 

 

 

Plot 2.2

 

 

 

 

Plot 2.3

 

 

 

 

Plot 2 Average

 

 

 

 

 

 

 

 

 

Plot 3.1

 

 

 

 

Plot 3.2

 

 

 

 

Plot 3.3

 

 

 

 

Plot 3 Average

 

 

 

 

Note: You will be reporting plot averages to the mapping site.