Field Notes

Twitchell Alfalfa: 2013-08-21 11:40:00 (DOY 233)
Author: Cove Sturtevant
Others: Joe, Laurie

Summary: Alfalfa was being bailed. Clipped remaining alfalfa near radiation boom. Found chewed SHF wire - fixed. Took measurements of 7500 orientation w.r.t. sonic.

Twitchell Alfalfa
2013-08-21

We arrived at 11:40 PDT. It was sunny, windy and warm (22 C). The alfalfa was being bailed as we visited the site. Joe went over to one of the bails and reported that it was extremely dense. The alfalfa has regrown to about 20 cm height. Joe and I attended to the tower while Laurie did LAI and clip plots. I did spectral later. We cut down vegetation around the solar panels and also the remainder of the alfalfa behind the radiation boom that we didnt get to last week.

7500 readings:
CO2 = 395 ppm (same after cleaning)
H2O = 630 mmol m-3 (same after cleaning)
SS = 92.9% (93.4% after cleaning)
T = 23.7 C
p = 101.3 kPa
sos = 347.7 m s-1

MET looked good except for SHF #1 reading NaN. Upon investigation I found a chewed wire. There was enough wire to cut and strip the wire above the chew and reconnect to the datalogger. The reading looked good after the fix. This reminded me to verify which serial nos were which:
SHF1: s/n 6342
SHF2: s/n 6498
SHF3: s/n 6491

Radiation looked good.

I took some measurements of the 7500 orientation with respect to the sonic: The 7500 is 33 cm to 120 N (magnetic) from the sonic.

Joe added a bolt to the post for the camera boom so that the boom rotated to about level and stopped.

5 photos found

20130821TA_TruckDitchWeeds.jpg ( 2013-08-21 12:26:42 ) Full size: 1920x1440
Cove doing spectral measurements in alfalfa field