SCMS95: SOIL Messages: 2 Entries..

Installation of soil sensors for PAMIII

The prepackaged soil sensor set which I had hoped to deploy for SCUM
still needs more work. Hence for SCUM it will be necessary to install
the three soil sensors the old-fashioned way.

In an area selected to be as representative as possible dig a small trench
   10cm(4") wide, 10cm(4") deep and 50cm(20")long. Save the dirt

 SOIL TEMPERATURE SENSOR
   Into the end face of the trench insert the temperature sensor at 45 degrees,
    angled downward to present the sensing element from 1cm to 7cm.
    Run the wire to the surface and away at a right angle to the trench.

 SOIL HEAT FLUX SENSOR
   Fill the trench bottom until it is 8cm deep and place the soil heat-flux
    plate, white dot uppermost, flat on the bottom of the trench, 2-3cm from
    the end of the trench. Run the wire along the bottom of the trench
    to emerge at the back end of the trench

 SOIL MOISTURE SENSOR
   Fill the trench until it is 6cm deep and place the dirt-bag 2-3cm behind
   the soil heat flux plate. The dirt-bag will extend from 2cm to 6cm depth.
   Run the wire along the bottom of the trench
   to emerge at the back end of the trench. Fill in the trench with the
   available dirt, packing it down to the original density. Use any rocks
   or pepples at the back end of the trench.

At 50-70cm(20"-30") from the end of the trench drive a stake into the
ground and secure the sensor cables with a panduit tie to make a strain relief

   surface ___________________________________________________
                                                             |   
   1cm                                                       | T
                                                             |  T
   2cm                              DDDDDD                   |   T
                                    DDDDDD                   |    T
   3cm                              DDDDDD                   |     T
                                    DDDDDD                   |      T
   4cm                              DDDDDD                   |       T
                                    DDDDDD                   |        T
   5cm                              DDDDDD                   |         T
                                    DDDDDD                   |          T 
   6cm                              DDDDDD                   |           T  
                                                             |            T 
   7cm                                                       |             T
                                                             |
   8cm                                            FFFFFFF    | 
                                                             |
   9cm                                                       | 
                                                             |
   10cm -----------------------------------------------------|
			      10  9  8  7  6  5  4  3  2  1  0
					     cm

To make gravimetric soil moisture determinations.

In the general area of the soil sensors dig a small hole 10cm deep, 
10cm wide and 10cm long. Using the square trowel with the 8cm index line.
take a soil sample from the surface to 8cm depth. Be careful not to bias
the sample. Load the soil into the appropriate plastic container.

In the trailer, empty the plastic container onto a sheet of plastic.
Remove any rocks and roots and homogenize the sample.
Make triplicate measurements of soil moisture for each sample.
Scoop approximately 20 - 30g aliquots of the soil sample into each
of the three Al cups. Tare the balance with a spare Al cup
and weigh the three aliquots.
Load the Al cups onto the tray and insert into the oven.

Allow the samples to cook for 24 hours in the oven set at 110 degrees C.
Remove the tray and allow to cool. Tare the balance and reweigh the aliquots.

                 Fresh       Dry       Difference      Diff/Dry
Sample A I       
Sample A II
Sample A III

Sample B I
Sample B II
Sample B III

Sample C I
Sample C II
Sample C III