Field Notes

<--2015-07-20 09:30:00 | 2015-08-06 10:30:00-->
Other sites visited today: East End | West Pond | Twitchell Rice | Mayberry

Twitchell Alfalfa: 2015-07-22 12:00:00 (DOY 203)
Author: Patty Oikawa
Others: Sara, Noah Amme

Summary: Field cut, spectral comparison, forerunners not doing well, 7500 swap

Arrived at 12pm. Sunny and very windy. They had recently cut alfalfa (few days ago), it has not been baled but biomass looked pretty dry.
Sara fixed the thermocouple on the FD chamberâ€”soldered in field. Sara also did spectral comparison with the 2 spectrometers. Sara downloaded data and swapped the 7500 (before swap sn 0065, after swap sn 75H-2150).
Noah clipped by hand around soil sensors. I took 6400 measurementsâ€”all values were around 13 Âµmol m-2 s-1. File 1 â€œTA_20150722â€ is collars 1,2,3,4,4b,5. File 2 â€œTA_20150722_Bâ€ is collars 6,5,1,4. I re-measured some collars due to strange valuesâ€”probably due to windy conditions and had to start a new file b/c power got disconnected by accident.
I forgot to check the ref temps, but next time check if 2cm is buried too low.
The 2cm forerunner probe was knocked out of place. I pulled it and the 8cm forerunner out and let equilibrate at ambient CO2, but neither responded much to the change. The 8cm probe read 4070mV in the ground and 3870mV in the air. The 2cm probe read 660 in 2cm depth and 659 in air. There is something wrong with the Forerunners but b/c it may be the program or voltages we left them installed for now.
7500 readings:
CO2 = 370 ppm (389 after swap)
H2O = 584 mmol m-3 (502 after swap)
signal strength = 82% (95.4% after swap)
p =
t = 27.9 C (28.3 after swap)
sos = 349 m s-1 (348 after swap)

5 photos found

TA_autocam_20150721_1215.jpg ( 2015-07-21 12:15:02 ) Full size: 1920x1440
Mowing