Field Notes

Twitchell Alfalfa: 2014-03-13 14:30:00 (DOY 72)
Author: Sara Knox
Others: Patty

Summary: Alfalfa growing. Standard fieldwork. Data download.

Twitchell Alfalfa
2014-03-13

We arrived about 14:30 PDT. It was partly sunny, breezy, and warm. The alfalfa has grown considerably since last week, which means we should start doing clip plots again (how I missed that...). I downloaded data while Patty did spectral measurements, measured vegetation height, tightened the RAD solar panel, and measured instrument heights.

7500 height: 307 cm above ground surface where the scaffold is installed, but that is about 30 cm below the alfalfa field. Therefore, the 7500 is ~277 cm above the alfalfa field.

I also tried swapping the 7500, however, when I installed the replacement 7500 (sn 2176) and uploaded the latest configuration file for that sensor the values were incorrect. Therefore, I re-installed the original 7500 (sn 0065) and brought back the replacement 7500 so that Joe could investigate this further in the lab.

7500 readings:
CO2 = 399 ppm (same after cleaning)
H2O = 307 mmol m-3 (309 after cleaning)
SS = 96.13% (96.45% after cleaning)
sos = 347 m s-1
t = 22.20
P = 101.5 kPa
Reservoir was also full, so I just topped it off.

MET looked good except for some low readings from SHF3 â€“ it reads about half of what the other SHF plates are reading (3.6 vs. ~6).

The radiation 10x did not have to be restarted this week.

We then drove back to Mayberry to pick up Joe and Cove.

Veg Height (cm): Tape measure from ground to top of plant
16, 18, 20, 16, 17, 14, 14, 15, 16, 15, 14, 17, 20, 13, 18, 14, 16, 16, 20, 25, avg = 16.7, stdev = 2.87

1 photos found

TA_autocam_20140312_0645.jpg ( 2014-03-12 06:45:02 ) Full size: 1920x1440
Geese on the field