Field Notes

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Twitchell Alfalfa: 2017-09-06 12:00:00 (DOY 249)
Author: Joe Verfaillie
Others: Kyle

Summary: Standard fieldwork, CSU East Bay team there for GPR survey, reinstalled FD chamber, cleaned up soil co2 a bit, fixed ground wire on Eosense 2cm probe.

Twitchell Alfalfa
2017-09-06

Kyle and I arrived at about 12:00. It was mild, sunny and hazy with a light breeze. The CSU East Bay Geology team was there setting up a big grid to the west of the tower for a GPR survey.

I swapped the 7500
sn 1594 off: 395.3ppm CO2, 842.5mmol/m3 H2O, 29.5C, 101.4kPa, 99.7SS
sn 0035 on: 408.1ppm CO2, 795.8mmol/m3 H2O, 29.6C, 101.4kPa, 99.8SS
There seemed to be relative larger fluctuations in CO2 and H2O both before and after swapping the heads.

Kyle took clip plots, veg height and did soil respiration. The soil respiration was so low that he set the thresholds on the 6400 to 375 +-5ppm.

I reinstalled the Forced Diffusion chamber sn FD20160001. I used the old cable to pull a new cable with a 90 degree connector into the conduit.

I removed two of the Vaisala power and communication boards that were used for the old Forced Diffusion chamber and were no longer used. I also removed an unused Vaisala cable and an unused Eosense cable. Both may have damage. I also found the ground lead on the 2cm Eosense probe was disconnected. I was planning to pull the probes for calibration but the data looks pretty good right now and with fixing the loose ground and removing the unused cables, I think the system is okay for now. I did disconnect the Eosense cables and I may have mixed up the 8 and 16 cables.

Veg Height (cm): Tape measure from ground to top of plant
8, 15, 9, 11, 11, 10, 7, 11, 9, 14, 9, 11, 8, 12, 17, 10, 16, 17, 20, 13, avg = 11.9, stdev = 3.55

2 photos found

twitchellalfalfa_2017_09_06_101610.jpg ( 2017-09-06 09:20:22 ) Full size: 1296x960
Ground penetrating radar