Field Notes

<--2021-07-06 16:40:00 | 2021-07-28 13:50:00-->
Other sites visited today: Hill Slough | Bouldin Corn

Bouldin Alfalfa: 2021-07-20 13:15:00 (DOY 201)
Author: Joe Verfaillie
Others: Daphne, Ariane, Carlos, Dennis

Summary: Set up extra sonics/tower for advection experiement, Fields being mowed today, clipped under tower, did FD performance check, spectral

Bouldin Alfalfa
2021-07-20

Daphne, Ariane, Carlos, Dennis and I arrived at 13:15. It was clear, sunny and warm with a nice breeze. Nearby fields have been mowed and a mower was working on the field immediately to the east while we were there. Alfalfa in our field was tall and thick - probably next for mowing. We trimmed the alfalfa under the tower but not at the PL Arable or the new Bouncer tower.

Daphne collected the tower data: flux, met, camera, FD, and IRT data. Ariane cleaned the flux and rad sensors. She also did veg height and spectral measurements. Dennis and Ariane cut alfalfa from three plots 45cm x 45cm and lumped them together for biomass.
The 7500 read: 401ppm CO2, 650mmol/m3 H2O, 27.8C, 101kPa, 100SS - 102 after cleaning
The 7700 read: 1.86ppm CH4, 15RSSI - 90 after cleaning.
The wash reservoir was 1/3 low and refilled but need to manually check the spray next time - RSSI < 30 and water left.

We unfastened the FD chamber sn FD20160001, set it on its side and ran a performance check on it. Soil co2 read 398.1ppm and ambient read 402.1ppm. We reset it to 400ppm and reinstalled the chamber.

The main task for today was to set up three extra sonic anemometers for Carlos's advection experiment. We have four sonics that we have inter-compered so we will replace the existing tower sonic with one of these from the inter-comparison. At the Tower the upper sonic at 393cm agl sn 153806 came off and sn 074417 went on. Then we added a lower sonic on a cross bar about 0.5m from the NW corner of the scaffolding on a heading of 293deg. The new sonic is sn 152601 and is at 242cm agl. Its analog outputs are fed into the LI-7700 inputs. Daphne made changes to the LI-7550 box setup so that these new channels are recorded in the standard 20Hz GHG files. The upper sonic heading is 253deg and the lower sonic heading is 352deg.

We set up a secondary (Bouncer) tower at 283m at 289deg from the main tower. The Bouncer tower is a ground screw anchor with telescoping post and surveyor tripod. Sonic sn 152603 went on top at 393cm agl and a heading of 19deg. Sonic sn 153805 went on a cross arm about 0.5m from the central post at 293deg and at a height or 242cm agl and heading of 353deg. Both sonics send analog data to a CR6 sn 2115 as single ended channels where it is recorded at 20Hz and 30min averages to a micro SD card. The system is running on a single group 27 deep cycle battery, 15A charge controller sn 03220377, and a 40W solar panel sn 04592G0181 .

We let at 15:20

Next Mowing: 2021-07-21

Veg Height (cm): Tape measure from ground to top of plant - Alfalfa probably mowed later this day or the next day
70, 75, 82, 74, 75, 73, 75, 85, 77, 70, avg = 75.6, stdev = 4.77

8 photos found

20210720BA_BouncerHat.jpg ( 2021-07-20 14:05:57 ) Full size: 1440x1920
Marking of the bouncer tower location

20210720BA_BouncerTower.jpg ( 2021-07-20 15:11:38 ) Full size: 1440x1920
Finished deployment of the year 1 bouncer tower

20210720BA_bouncerinstallation.jpg ( 2021-07-20 14:22:23 ) Full size: 1920x1440
Carlos, Dennis, Joe and Daphne installing the bouncer tower for the

20210720BA_bouncersonics.jpg ( 2021-07-20 14:49:54 ) Full size: 1920x1440
Joe and Carlos setting up the 3D sonics at the bouncer tower for the advection experiment