SOIL MOISTURE OBSERVATIONS IN TUCSON, ARIZONA
Here is some data I have been collecting:
My site is a field near a dry river (a "wash") so the soil is very sandy and
uniform. The soil becomes slightly coarser below 60 cm and it is very
difficult for me to recover core samples this deep when the soil is
dry (which is most of the time). Let's first look at a bar plot of
precipitation, which is the source of most soil moisture.
- Precipitation
Note: The precipitation spike of 50 mm corresponds to a period when the
field I am studing was flood irrigated.
- My calibration curve at 10 cm and 30 cm
Note: Hopefully, your calibration curve has more points in the middle range
than mine does. You might need a simple exponential function to fit your
curve - I have too much scatter to justify this. After I look at each
school's calibration data, I will be able to specify a general equation
we all use to find a best-fit line. I used the 30 cm calibration curve to
transform each meter reading to gravimetric soil moisture, as is required by
the protocol.
I have plotted all my time-series versus
Day-of-Year or Julian day (i.e. every day of the year gets a unique
and steadily increasing value so DOY 224 = Aug 12 and DOY 334 = Nov 30).
- Soil Temperature
Note: In general, early morning
temperatures are the minimum for the day. If you measured temperature all
day, what would it look like as you go deeper?
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Last updated: 11/19/96
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