Soil Moisture

Step 4: Soil Moisture

Materials

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

Methods:  Preparing the LabQuest2 Soil Moisture Sensor

--Using the stylus, tap the home icon at the bottom of the screen and highlight LabQuest2 Apps.  Open a “New” File by tapping on “File” (upper left) and highlighting new.

--Plug in the soil moisture probe into the CH1 port at the left of the LabQuest2 unit. 

The LQ2 unit will begin reading soil moisture, even before you place the sensor in the soil.

-- Tap on the mode box (left column).  Tap on the dropdown arrow on the right side of the mode window.  Highlight Data Matrix (bottom of the list).  Enter “Depth” in the “Name for Rows” box and “Plot 1” (or Plot 2/Plot 3—depending on the plot you are sampling) in the Name for Runs box.  When you click on the box containing the default names, a keypad will pop up and you can edit the names.

--Tap “Done” and “Ok” to save the new names.

--Put the unit aside and prepare your sample point.

 

Methods:  Soil Moisture Sampling

--Return to your first soil temperature sampling point.  You will use the same hole to collect soil moisture data.  If you did not widen your hole when collecting your soil temperature data, you will need to widen the hole to accommodate the soil moisture probe.

Note:   Do not widen the hole greater than 15 cm x 15 cm. 

--Begin by widening the hole to a depth of 5 cm.  Place the soil you remove on the sheet with the other soil you removed from the hole to a depth of 5 cm, during soil temperature sampling process.   

--Continue widening the hole to a depth of 10 cm.  Place the soil you remove from the 5 cm—10 cm range on the corresponding sheet.

--Continue widening the hole to a depth of 20 cm.  Place the soil you remove from the 10 cm—20 cm range on the corresponding sheet.

--Continue widening the hole to a depth of 30 cm.  Place the soil you remove from the 20 cm—30 cm range on the corresponding sheet.

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.

--Using a pencil or similar implement, loosen the soil in the side of the soil profile—at the 5 cm depth.  Gently insert the soil moisture probe horizontally, but oriented on its side (like a knife), into the loosened soil of the profile. 

-- Tap green collection arrow (bottom left).  At this time, a new screen will appear which will allow you to add additional plot columns for your sample points and additional depth rows for your sample depths, to your table.  After your sample point and depths have been added, it will also be the screen you can use to change the sample point and depth you are working on.

--Tap “Add Plot 1” 2 times so that the number 3 appears in the upper left window (indicates the number of points at which you will be collecting soil moisture samples within your plot).

 --Tap “Add depth” 3 times so that the number 4 appears in the upper right window (indicates the number of depths at which you will take readings at your current plot and sample point). 

1 = 5 cm, 2 = 10 cm, 3 = 20 cm, and 4 = 30 cm.

--Make sure number 1 appears in the “Plot 1” window and in the “depth” window when you take your 5 cm moisture reading at the first sample point in Plot 1.

--Tap on Continue (bottom right) and you will be taken to the Soil Moisture sensor screen.  Once the Soil Moisture value stabilizes (the number stays constant for ~10 sec.), tap on the stop button (bottom left of screen).

--To view your recorded data, tap on the table icon (x|y) at the top of the screen.

--Return to the sensor screen by tapping the meter icon (upper left of screen).

Tip:  If you need to retake any readings, simply tap on the green collection arrow, make sure that the right depth is selected, tap continue, tap on the value, and tap the value again once it stabilizes.  The most recent reading will be saved in the table.

--Gently remove the soil moisture probe from the hole.  Do not pull the probe out by the wire.  Loosen the probe by digging in the area around the probe.  Once the probe is removed, wipe it clean with distilled water and gently dry with a paper towel.  

-- Using a pencil or similar implement, loosen the soil in the side of the soil profile—at the 10 cm depth.  Gently insert the soil moisture probe horizontally, but oriented on its side (like a knife), into the loosened soil of the profile. 

-- Tap green collection arrow (bottom left).  Make sure number 2 appears in the “depth” window when you take your 10 cm moisture reading.

--Tap on Continue (bottom right), and you will be taken to the Soil Moisture sensor screen.  Once the Soil Moisture value stabilizes (the number stays constant for ~10 sec.), tap on the stop button (bottom left of screen).

--To view your recorded data, tap on the table icon (x|y) at the top of the screen.

--Return to the sensor screen by tapping the meter icon (upper left of screen).

--Gently remove the soil moisture probe from the hole.  Do not pull the probe out by the wire.  Loosen the probe by digging in the area around the probe.  Once the probe is removed, wipe it clean with distilled water and gently dry with a paper towel.  

-- Using a pencil or similar implement, loosen the soil in the side of the soil profile—at the 20 cm depth.  Gently insert the soil moisture probe horizontally, but oriented on its side (like a knife), into the loosened soil of the profile. 

-- Tap green collection arrow (bottom left).  Make sure number 3 appears in the “depth” window when you take your 20 cm moisture reading.

--Tap on Continue (bottom right), and you will be taken to the Soil Moisture sensor screen.  Once the Soil Moisture value stabilizes (the number stays constant for ~10 sec.), tap on the stop button (bottom left of screen).

--To view your recorded data, tap on the table icon (x|y) at the top of the screen.

--Return to the sensor screen by tapping the meter icon (upper left of screen).

--Gently remove the soil moisture probe from the hole.  Do not pull the probe out by the wire.  Loosen the probe by digging in the area around the probe.  Once the probe is removed, wipe it clean with distilled water and gently dry with a paper towel.  

-- Using a pencil or similar implement, loosen the soil in the side of the soil profile—at the 30 cm depth.  Gently insert the soil moisture probe horizontally, but oriented on its side (like a knife), into the loosened soil of the profile. 

-- Tap green collection arrow (bottom left).  Make sure number 4 appears in the “depth” window when you take your 30 cm moisture reading.

--Tap on Continue (bottom right), and you will be taken to the Soil Moisture sensor screen.  Once the Soil Moisture value stabilizes (the number stays constant for ~10 sec.), tap on the stop button (bottom left of screen).

--To view your recorded data, tap on the table icon (x|y) at the top of the screen.

--Gently remove the soil moisture probe from the hole.  Do not pull the probe out by the wire.  Loosen the probe by digging in the area around the probe.  Once the probe is removed, wipe it clean with distilled water and gently dry with a paper towel. 

--Save your soil moisture data for your sample point.  Tap on “File,” highlight “Save,” and tap on the title window.  A keypad will pop up and you can title your file: firstinitiallastnamesmp# (e.g. ljonessmp1).  In this case, you would be saving your soil moisture data (sm) for Plot 1 (p1).  Tap on “Done” and “Save.”

You can use the following table to record your observations (in addition to saving data to the LabQuest 2 Unit).  Note that you will be reporting plot averages to the online map.

Table 2: Soil moisture data from XXXXX (your site name).

Sample

Soil Moisture

5 cm (%)

Soil Moisture

10 cm (%)

Soil Moisture

20 cm (%)

Soil Moisture

30 cm (%)

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

 

 

 

 

 

Soil Moisture Methods for your remaining sample points and plots

--Move to your second sample point in your plot.  Return to the sensor meter screen (using the sensor meter icon in the upper left corner) position your soil moisture probe as described above and tap on the green collection arrow at the bottom left.  Change the number in the “Plot 1” window to read 2 (indicating that the data you are collecting is from the 2nd sample point in Plot 1) and be sure to change the number in the “depth” window back to 1 (indicating that you are taking a reading at the 1st depth/5 cm). 

--Follow the methods described above for your remaining sample points.

--For each plot, you will have a separate soil moisture file which contains the soil moisture data you collected from all of the sample points within each plot.  Before moving to your next plot, be sure to save your data.  Then, open a new file for the next plot and follow the instructions above. 

--When you save the soil moisture data for your next plot, be sure to give the file a new name which indicates the plot number.   Title your file using the same format you used for Plot 1— firstinitiallastnamesmp# (eg. ljonessmp1, ljonessmp2, ljonessmp3, etc.).