Friday, July 25, 2014

HOBO Temperature Sensors

[Update 4/8/16] --Removed sensors so Kye could drill the field yesterday and replaced them today at 1:30pm.  I'm down to 5 sensors in two locations.  The heavy mowed residue site has three (#6@ 3", #9@1", #4 in the air near surface).  The bare earth site has #7@1",  #8 in the air near surface. [#8 was in tall stubble but drilling dragged all material away.
[Update 2/24/16] --Launched two sensors for air temperature just above the soil surface, --#8 in the tall stubble, --#4 in mowed area.  Should have thought of this earlier, but the thought never surfaced until a farmer suggested that tall stubble may have trapped cold temperature to the point of reducing the survival of his winter canola.  I have my doubts but there is no reason not to check it out.  Another sensor (#11) was carried off by some animal.  I found it about 30' from its flagged location (that was luck).  I have no idea of how long it was on  the surface but I have put it back in the ground in the tall stubble, --which is mostly been flattened from winter weather of wind and a little snow.  The roots are rotting, or being eaten off and allowing the plant to tip over when the forces of wind, water, snow engulf them.  This sensor in the tall stubble has not been bothered in the past as those out in the open have.  Now that it is exposed it is experiencing similar attention from critters.  I'm going to have to stake and tie these sensors more securely in the future.
[Update 1/8/16] -- Relaunched sensors from being pulled out in November.  The sensors were set for readings every 2hrs instead of 1hr.  --#1 is located under #7(bare grnd) for temperature reading ≈3" deep.  # 8 was not relaunched (couldn't locate plank).  #6 is under #9 (under heavy mowed residue).  #3 under #10 (standing residue w light surface residue).  Replaced snow cover.  Soft frost found at (bare grnd) site.
[Update 7/27/15] -- #11 HOBO has disappeared.  It is being replaced today with #E7.  It appears that the crows/ravens are drawn by the bright fluttering flags used to mark the location of the HOBO's.  They haven't bothered the flag in the tall stubble, but all flags in the mowed areas are decimated, and I can only assume they packed off the small HOBO sensor.
[Update 6/14/15] -- placed four HOBO's (#8-9-10-11) (8am, 6/14/15), in Ee field.  #8 is placed under white board on grnd that had been bared.  #9 is placed in very heavy residue that was mowed.  #10 is placed in standing residue with little surface cover.  #11 is placed in bare grnd that had been scraped clean of residue.  All the sensors are placed near each other, and vertical at the surface.
     Intention is to pull them for readings on the 22nd prior to the drill demo,  then again this fall when the field is seeded.  We'll take moisture samples at that time as well.
[Update 6/4/15] -- pulled #1 through 7 to download.  No data was recovered.  A wasted 6m.
[Update 10/30/14] -- pulled and downloaded sensors ≈ Oct. 23 and replaced them on Oct 30th.  Units #6&7 were switched when placed back in the soil.
This past year I have been playing with temperature sensors with the intent of quantifying the impact that the stripper header, and residue on the soil surface has on seed zone temperatures.  Last year I played around with them to get an idea of what they were capable of.  These units can be left in the field to collect data for a lengthy period of time.  You can down-load the data on a computer and graph in many different ways.   This summer I'm starting over with all the HOBO's positioned vertically with the top of the unit at the soil surface.  Seven total.  At the time of placement I took the soil temperature of each location as a start point.  I will update this post when something of interest pops up or at season end.
    ------[field Es]-- Two units are in a chemical fallow field with heavy residue that is totally flat to the ground. One of these units is placed in an area of heavy residue(#7) where no dirt can be seen.  At 2" my soil thermometer indicated 82 degrees.  The other one was place where dirt could be seen at the surface(#6).  The temperature at that spot was 90 degrees. This field location has a slight slope to the north.
     ------[field Ee]--Three units were placed in a chemical fallow field that was stripper headed.  There is heavy residue with stubble standing approximately 36" tall.  One unit was placed in a combine wheel track where there was some dirt showing and the residue was pressed flat to the ground (#3).  The combine had duels mounted close together, so the track is wide.  The temperature at that site was 96 degrees.  A second unit was located in an area with tall standing stubble and no residue covering the ground surface (#1).  The temperature at that site was 80 degrees.  The third unit was placed in a location that had tall standing stubble and also had the ground surface covered with residue (#4).  The temperature at that site was 72 degrees.  This field location is flat
     ----- [field En]--Two units were placed in a growing spring barley field.  The barley is only around 22" tall and fairly thin.  One unit place in heavy residue (#2).  The temperature at that site was 82 degrees.  The other unit was placed whee there was no ground surface cover (#5).  The temperature at that site was 84 degrees.  This field location has a slight slope to the south.
        SUMMARY:
     --- In field Es I was surprised that there was so little difference in the temperature between the two sites.  Did the flattened residue have an impact???
     ---In field Ee I was surprised that the wheel track showed such a high temperature compared to the other two sites.  The wheel track was more compacted.  Did that influence the temperature???  The tall stubble seems to be impacting the temperature compared to the field with the flattened residue.
     ---In field En I was surprised that the temperature was so similar between the two sites.  Does a growing crop influence the surface temperature more than the surface residue???

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