Field Notes

Twitchell Alfalfa: 2014-09-25 14:00:00 (DOY 268)
Author: Cove Sturtevant
Others: Dennis, Sara

Summary: Field wet farther out in footprint. Huge soil respiration. Couldn't find collar #1. Reinstalled soil CO2 probe & 2 thermocouples and added protective tubing to wires.

Twitchell Alfalfa
2014-09-25

We arrived at about 14:00 PDT. It was partly cloudy and warm. The ditch leading to the tower was full of water after about Â½ way to the tower (we didn't get stuck - woo!). Dennis reported that the field was wet/irrigated out further in the footprint, but not closer to the tower. Alfalfa continues to regrow.

Dennis did veg height and spectral. Sara did soil respiration but couldnâ€™t find collar #1. She recorded huge fluxes (25-30 umol m-2 s-1 !) after the rains late last night and this morning. Dennis and Sara added protective tubing to all the soil CO2 probe wires that have been recently chewed. I reinstalled the 8 cm probe (sn 1340007) and thermocouple in profile 1 and also redug this hole. Also swapped out the thermocouple for the surface probe in profile 1 because it was chewed. All readings looked decent after fix.

7500 readings:
CO2 = 334 ppm (403 after cleaning)
H2O = 760 mmol m-3 (610 after cleaning)
signal strength = 65.4% (83.4% after cleaning)
p = 101.4 kPa
t = 22.8 C
sos = 347.0 m s-1

Veg Height (cm): Tape measure from ground to top of plant
22, 20, 28, 21, 10, 9, 21, 20, 14, 21, 15, 21, 21, 20, 26, 14, 21, 12, 0, 15, avg = 17.6, stdev = 6.48

1 photos found

TA_autocam_20140925_1345.jpg ( 2014-09-25 13:45:02 ) Full size: 1920x1440
Cove, Dennis and Sara on site