Field Notes

Bouldin Alfalfa: 2021-03-16 12:10:00 (DOY 75)
Author: Daphne Szutu
Others:

Summary: Regular data collection/cleaning, alfalfa looks chewed, AirT drifting low since January--swapped HMP sensor

2021-03-16
Bouldin Alfalfa

I arrived at 12:10 PDT. It was cool with a cold breeze. Most of the field looks like it has been chewed by birds again, although there are still the green, lush areas around our tower and under the PL Arables.

Camilo removed the 7700 last week to install at Hill Slough. Today I disconnected the 7700 in the 7550 software and disconnected the 7700 power cord from the 24V pluggable power strip in the met box.

I downloaded met, camera, and USB GHG. I downloaded the FD data and cleared its memory. I cleaned flux and rad sensors.

I changed RH/AirT sensors because the HMP60 AirT has been drifting low since January: HMP60 sn G4540021 came off and HMP155A sn S3420870 went on. The HMP60 was wired as a single-ended measurements, but the mux port next to it was empty because of a removed barometer. I wired the HMP155 as a differential measurement (using both the HMP60 and barometer mux ports) and powered it continuously with the 12V pluggable power strip. I uploaded a new CR1000 program with the new HMP155 instructions and coefficients.

The HMP155 fan wasnâ€™t working (it was a used fan but it was in my bag oâ€™ fans, so I thought it was good), so I had to use the fan I had just removed from the HMP60. AirT was 14C and RH was 39%, which seemed reasonable. The HMP155 shield has 2 all-thread bolts which donâ€™t slide down as easily as the partly threaded bolts, so you have to wiggle them a bit, but I think itâ€™s better than the bolts dropping immediately after you unscrew them from the top layer of the shield.

LI-7500 readings:
CO2 420ppm
H2O 320ppm
T 15.3C
P 101.3kPa
SS 101--> 101 after cleaning

I left at 13:30 PDT.

Next Mowing: 2021-04-25

1 photos found

bouldinalfalfa_2021_03_16_114506.jpg ( 2021-03-16 11:48:38 ) Full size: 1296x960
Daphne swapping HMP sensors