Field Notes

Twitchell Alfalfa: 2018-04-05 11:50:00 (DOY 95)
Author: Daphne Szutu
Others: Elke, Kyle

Summary: Regular data collection/cleaning, soil respiration, biomass samples, veg height, swap 7500 for calibration, install forced diffusion chamber

2018-04-05
Twitchell Alfalfa

We arrived at 11:50. It was overcast, cool, and breezy. The field is mostly grass, with some nettles and rare alfalfa. We drove by a bird popper (propane cannon) in the field east of the tower on the way from EE, but didnâ€™t hear it go off while we were at this site.

Elke and Kyle did clip plots (biomass samples) and took veg height measurements. I collected met, camera, soilco2, and USB GHG data. I also swapped the 7500: sn 1594 went up, and sn 75H-2514 came down. I uploaded a new config file, updated the pressure coefficients, and re-set the LI-7550 box.

LI-7500 readings (sn 75H-2514 --> sn 2514 cleaned --> sn 1594)
CO2 410ppm --> 407 --> 410
H2O 450ppm --> 460 --> 450
T 16.2C --> 16.2 --> 16.4
P 102 kPa --> 1012 --> 102.1
SS 102 --> 104 --> 100.6

Kyle did soil respiration, with collars in this order: 1, 2, 4, 3, 5, 6. The first appended file stopped midway. He reduced the target to 375 +/- 5, because the measurement was taking very long and the efflux was low.

I reinstalled the forced diffusion chamber, sn FD20160001. I attached the chamber springs to the anchors with zipties, which seems itâ€™ll work ok for the next two months. We connected to the chamber through the eos software; the chamber time was set to 4018-03-05, so Elke synced it with the system time. We changed the frequency from 10 min to 5 min. Elke tried to download the data, and the software gave us a success message, but there was no new file in the appointed directory, maybe because 10 minutes had not passed since power-up. We then checked the time again and it had reverted to 4018-03-05, so we just left it was is. Next time we could try power cycling the chamber to save the configuration settings.

Elke cleaned the solar panels, which were very poopy. Kyle cleaned the Arable and Arable solar panels and the rad sensors. I replaced the temporary battery cables with thicker-gauge battery cables. Elke put split loom on the exposed solar cable.

We left at 13:00.

Veg Height (cm): Tape measure from ground to top of plant - Mostly grass
51, 64, 59, 56, 55, 44, 57, 66, 53, 54, 17, 22, 29, 46, 52, 59, 55, 64, 42, 64, 55, avg = 50.7, stdev = 13.45

1 photos found

twitchellalfalfa2_2018_04_05_111505.jpg ( 2018-04-05 11:15:28 ) Full size: 1296x960
Elke in the field