Field Notes

Twitchell Alfalfa: 2017-03-29 11:20:00 (DOY 88)
Author: Daphne Szutu
Others: Elke Eichelmann, Kyle Hemes

Summary: Regular data collection/cleaning, clip plot, veg height, NR01 PRT number was NAN, tried to update forced diffusion chamber firmware but brought chamber back to the lab

2017-03-29
Twitchell Alfalfa

We arrived at 11:20. It was sunny and clear, warm with a light breeze. There were sheep grazing to the west of the tower, about 100m from the tower.

Elke did 5 clip plots (biomass) samples. Kyle took 20 veg height measurements. The alfalfa look terrible -- lots of grass and nettle and very little actual alfalfa cover near the tower.

Kyle did 8-10 spectral measurements. It was mostly clear, some constraints. The alfalfa was very heterogeneous, so he tried to measure mostly over alfalfa spots. The measurements were saved around 00040.5az to 00048.5az (will be timestamped).

Kyle took soil respiration measurements. The analyzer complained about high humidity but worked well otherwise.

I collected met, soil CO2, and USB GHG data and swapped the camera card. I had trouble connecting to the soil CO2 datalogger at first, but it worked after I power-cycled the soil CO2 datalogger twice and re-connected and disconnected from the met datalogger (to make sure the cable and the USB port were okay).

The NR01 PRT reading was NAN. The wiring seemed to be fine and we could see a flicker of voltage coming across VX1 about every 10 seconds. Not sure what was wrong with the PRT sensor or wiring.

We cleaned the radiation and EC sensors and put new bird spikes on LI7500.

LI7500 readings:
CO2 414.6 umol/mol
H2O 511.9 mmol/m3
T 20.9 Celsius
P 102.2 kPa
SS 90.8 -> 92.1 after cleaning

I downloaded the forced diffusion data using eosLink-FD_v2.3.3.exe and then deleted the data from the analyzer. I disconnected power and ran the software to update the chamber firmware (Reprogram_FD.bat). I tried the .bat file a few times b/c it had trouble find the COM port. The first time I successfully started the upgrade process, I closed the .bat window too early before the process completed, so I re-ran the .bat file and closed it after I saw "Programming complete" in green text. I tried to connect to the chamber again using eosLink-FD_v2.3.3.exe, but could not connect. We brought the chamber back in to the lab for testing.

We left at 12:45.

Veg Height (cm): Tape measure from ground to top of plant
23, 28, 24, 25, 25, 22, 32, 19, 17, 18, 21, 19, 26, 25, 18, 27, 15, 24, 42, 23, avg = 23.7, stdev = 6

1 photos found

twitchellalfalfa_2017_03_29_085124.jpg ( 2017-03-29 07:05:04 ) Full size: 1296x960
Sheep