Field Notes

Twitchell Alfalfa: 2018-02-28 11:40:00 (DOY 59)
Author: Daphne Szutu
Others: Elke, Alex, Sigrid

Summary: Regular data collection/cleaning, clip plots, veg height, LAI, cloudy spectral

2018-02-28
Twitchell Alfalfa

We arrived at 11:40. It was cool and slightly cloudy with high, thin clouds and a light breeze. The field is a mix of grass, nettle, and alfalfa.

Elke collect met, soil co2, camera, and USB GHG data. She cleaned the rad and flux sensors. Alex and Sigrid did clip plots (biomass samples) and veg height measurements. Sigrid did spectral measurements, even though it was cloudy. We did not do soil respiration measurements because I forgot the battery.

I took LAI-2200 measurements. I took above measurements with the above wand. With the below wand, I took 10 above measurements and 20 below measurements (2 transects of 10, walking in the flux footprint towards the N). Calculated LAI ~1.5. I then took 10 more below measurements, focusing on wedging the sensor below the vegetation, which could make a difference since I didnâ€™t specifically wedge the sensor underneath the grass in the first 20 below measurements.

LI-7500 readings:
CO2 412 ppm
H2O 353 ppm
T 14.7 C
P 102.2 kPa
SS 102 --> 104 after cleaning

We left at 11:40.

Veg Height (cm): Tape measure from ground to top of plant - 1st set W transect, second N
7, 17, 6, 15, 13, 11, 18, 10, 6, 14, 15, 23, 12, 10, 8, 7, 18, 13, 5, 6, avg = 11.7, stdev = 4.99

1 photos found

twitchellalfalfa_2018_02_28_114506.jpg ( 2018-02-28 11:46:22 ) Full size: 1296x960
Daphne, Sigrid, Alex, clip plots