Soil samples

As part of soil sensor installation, I asked John to collect a soil sample at each site.  The primary reason is to have the soil bulk density, which is needed to convert from the EC-5 volumetric sampling to gravimetric values.  He brought these samples back to Boulder for analysis several days after sampling.  Clearly, after all this time, we expect the soil moisture to be lower than when the sample was taken, since moisture can evaporate from the sample.  Nevertheless, the values below could be used as a lower bound of the EC-5 values.  (Though the EC-5 itself is expected to have measurement issues due to soil settling.)  Note that for museum, the EC-5 reading was indeed lower than the gravimetric sample, indicating that this sensor had not settled into the soil.

The cores were transported still in the brass ring (which would have helped reduce drying of the core).  In processing these cores, the ring needed to be removed to stay within the mass range of the scale used.  Even so, the airport core was too heavy, so it was split into 2 trays, hence the sums of numbers below.

tare = c(2.10+2.33, 2.10)

wet = c(111.14+8.10, 115.21) - tare

dry = c(88.12+14.26, 94.16) - tare

vol = c(3)*pi*(5.31/2)^2

moist = 100*(wet-dry)/vol

rho = dry/vol