Field Notes

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Twitchell Alfalfa: 2016-03-02 09:00:00 (DOY 62)
Author: Joe Verfaillie
Others: Elke

Summary: Sheep gone, soil sensor wires cut be farm equipment - all soil sensors removed, other chewed wires spliced, FR co2 one cable chewed, field reseeded maybe.

Alfalfa
2016-03-02

I arrived about 9:00 with Elke. It was foggy and cool at the coast but it quickly cleared off and was warm and sunny in the Delta. There was little to no wind. There were lots of geese on the fields. We came to repair the damage done by the sheep.

The sheep were gone, nowhere in sight. The wire fence was still in place but beat down in a couple places and there were muddy hoof prints on the solar panels. We removed the fence between the tower and the field. Elke began to pull up the soil sensor cables and discovered they had all be cut into sections by some farm equipment that had been drag over the field. Whatever it was, it was relatively sharp and only went down about 10cm. The soil did not look disturbed in front of the tower, but other places in the field the soil was clearly broken. We saw a farmer shooting whistlers at the geese to scare them off and after talking to Housen I think they reseeded the field. On our way out, there was a tractor spraying something on the field. The driver was in an enclosed cab but didnâ€™t seem to be wearing protective equipment and there were no obvious warnings on the tanks. But, it might be Roundup. There were lots of nettles growing in the field that the sheep did not eat.

So with all the wires cut we removed all the soil sensors: SHF plates sn 6498,sn 6342,sn 6491; Theta probes sn 377/008, sn 377/010; and three thermocouple profiles.

I spliced sheep chewed wires from the diffuse PAR sensor, shadow band motor and sensor, and camera power. The HMP60 wire was also chewed. It is still working, but the cable is no longer weather proof and needs to be swapped out next time. I replaced the power wire for the HMP60 fan, and then the fan itself. I also cleaned out a bunch of spiders and webs from inside the shield plates.

The 7500 read: 405.8ppm CO2, 501.1mmol/m3 H2O, 88.48SS, 18.61C, 101.7kPa
The temperature sensor is still erratic and needs replacing.

The power line to the solar radiation and soil co2 systems was cut and its fuse blown. I spliced the wire and left it lying on the surface. I put in a new 5A fuse. Elke collected the soil co2 and solar radiation data. The first Forerunner CO2 probe was not reporting. Looks like squirrels chewed on its cable. It needs a new cable next time.

We put new bird spikes on the sonic. We took the sonic down to do this and were careful to mark the orientation so that it could be replaced properly.

I cleaned the solar panels. We collected the camera images and the Licor GHG data.

The distant from the tower to the soil co2 box is about 13m â€“ new conduit protected power line next time.

2 photos found

TA_autocam_20160303_0845.jpg ( 2016-03-03 08:45:03 ) Full size: 1920x1440
Geese on the field