Field Notes

When: Apr 11, 2002
Where: Tonzi/Vaira Ranches
Who: Liukang Xu & Ted

Weather: In the morning, clear sunny, in the afternoon, increasing cloud. Now is the best time to enjoy the scenic view. Grass is green, and oak leaves are just about 2 weeks old.

Around 9:30 arrived at Tonzi ranch,

At Tower:

Electric fence working. Flux system was running continuously since d95. PV controller reading, 14.0V, 14.6A, 2.3A. CR23X battery 12.8V. Li-Cor7500 0065.

Download data, restart the laptop, gillsonic reading, Tsonic=23.3C, q_v=2.568, CO2_V=1.734. Ted swapped sonic in the pm, he also installed a small solar panel for the fence battery.

AT FLOOR;

Fence working, flux program was on, also continuously running since last time Ted & Dennis’s visit. PV controller reading; 13.7V, 139A, 1.7A. Battery fully charged.

In PM, Ted replaced Li-Cor 7500 0073. sn 0073 came down and sn 0035 went up.

Download data. After reboot laptop, gillsonic reading, Tsonic=27.48C, q_V=2.928, CO2_V=1.748.

Ted installed a small solar panel for the fence battery.

Soil point moisture reading;

Soil moisture start to decrease, esp for the top layer.

Dendrometer reading

Grass height measurement (n=20, m=10.8 cm, std=4.5 cm)

Oak leaf sample from 6 trees for leaf development and N content data.

Finished 2 A/Ci curve. After I done A/Ci curves, dark respiration measurement (set PAR=0, Ca=360 ppm), Rd was 4.2 and 3.3 umol/m2s.

Pressure chamber problem: Air can not release from the chamber. Ted said the valve might have some problems. Took back to the lab.

At Vaira 4:45 pm

Cloudy, no cow around. Fence and flux system working. Flux system also continuously running. Download data, checking communication between data logger and laptop. PV reading: 12.5V, 3.6A, and 3.3A.

Took soil point moisture reading (see above table).

Grass height measurements (n=20, m=23.2cm, std=8.4 cm)

Ted swapped the sonic