Field Notes

Bouldin Corn: 2024-06-03 12:30:00 (DOY 155)
Author: Daphne Szutu
Others: Arman

Summary: Checked sonic orientation, installed well and water level sensor, swapped tower power cable, dfPAR motor dying and needs replacement

2024-06-03
Bouldin Corn

Arman and I arrived around 12:30 PST (13:30 PDT). It was sunny and warm with a strong breeze from the west. Our corner of the field (the south east corner) is weedier than the rest of the field—they probably avoided our tower while spraying the field with herbicide.

I showed Arman how to check the sonic orientation using our phone compass. We set our phones to true N and compared them to each other. At first, they were about 10 degrees off. We then waved our phones in a horizontal figure-eight pattern in front of us. This brought our phones’ to 1-2 degrees of each other.

Arman took four measurements of the sonic orientation, two with each of our phones. The average was 347 degrees true N.

I got started with replacing the power cable going from the white power enclosure to the tower. I unplugged the white power plug in the enclosure. When we moved the tower closer into the field, I had to splice on some extra cable to make it reach. Today I swapped out the spliced cable with an 18 AWG power cable in metal conduit. I thought I would have some extra cable, but of course it turned out just right. I plugged the white power plug back in and downloaded data.

Arman dug a new hole for the well and installed the water level sensor just above the bottom of the well (he lowered it down to the bottom of the well and then pulled it up a few cm). The well is dry and the sensor was 90cm below the ground surface.

I collected met, cam, USB GHG, and PA data. I downloaded data from the two zcams and confirmed that their clocks were good. The Apogee NDVI sensors aren’t working, even after a power cycle. Not sure what’s wrong. The tower NDVI sensors haven’t lasted for long, so we could probably remove all of them (and the PRI sensors, too).

The rotating shadow band was not spinning, but it started again after I adjusted some of the wires in the motor enclosure. It will probably work for a day or two again before stopping. I need to replace this motor.

Arman topped off the wash reservoir, cleaned flux and rad sensors, and measured veg height.

The 7500 read: 405ppm CO2, 810mmol/m3 H2O, 27.2C, 101.3kPa, 99SS – 101 after cleaning
The 7700 read: 1.87ppm CH4, 42RSSI – 79 after cleaning

We left at 13:30 PST (14:30 PDT).

Looking at the data back in the lab, the Apogee NDVI data seems complete in the last 2 weeks. I'll look at it again during our next visit.

Veg Height (cm): Tape measure from ground to top of plant - Avoiding weedy area just west of the tower
9, 23, 25, 13, 18, 23, 20, 21, 16, 22, avg = 19, stdev = 5.03

0 photos found

6 sets found

17 BC_met graphs found