Field Notes

Twitchell Alfalfa: 2014-11-11 11:05:00 (DOY 315)
Author: Cove Sturtevant
Others: Joe, Sara, Hisashi, Pascal, Sam

Summary: Collected data. Minor maintenance. Regular fieldwork. Fixed SHF #2.

Twitchell Alfalfa
2014-11-11

We arrived at about 11:05 PST. It was overcast, windy, and cool. I checked the tower and downloaded data while Joe did maintenance on the soil CO2 system, he replaced the ad-hoc 10kohm voltage dividers with 499kohm dividers. Sara did spectral and soil respiration, Sam and Pascal did veg height. Hisashi made 0-second videos complete with soundtrack.

7500 readings:
CO2 = 312 ppm (402 after cleaning) â€“ TONS OF SPIDER WEBS
H2O = 813 mmol m-3 (540 after cleaning)
signal strength = 69.48% (84.89% after cleaning)
p = 101.2 kPa
t = 18.2 C
sos = 345.4 m s-1

SHF #2 was NaN, found the wire chewed by squirrels. Fixed.
Rad good.

Soil respiration notes:
#1: 1.1 umol m-2 s-1
#2: 2.7 umol m-2 s-1 (after #2, set target to 380 ppm since ambient was reading 370)
#3: 0.9 umol m-2 s-1 (only 2 reps, stopped rep #3 â€“ 1 empty file)
#4: 4.3 umol m-2 s-1 (#â€™s 4-6 dCO2 = 5ppm, 2 cycles only to speed things up)
#5: 1.8 umol m-2 s-1
#6: 2.8 umol m-2 s-1

Veg Height (cm): Tape measure from ground to top of plant
26, 12, 20, 10, 15, 9, 15, 19, 15, 18, 20, 11, 13, 15, 19, 8, 22, 15, 7, 12, avg = 15.1, stdev = 4.99

2 photos found

20141111TA_SamPascal.jpg ( 2014-11-11 12:22:03 ) Full size: 1920x1440
Sam and Pascal cleaning solar panels at Aflalfa