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Gravimetric processing from samples taken using corer.

Date/TimeLocationTare (g)Wet (g)Dry (g)Density (g/cm^3)Qsoil (cm^3/cm^3) %EC5 Reading (cm^3/cm^3) %Diff (cm^3/cm^3) %
20 Feb 2015/1157bao, 2--5cm5.58100.7483.541.1725.8923.981.9
20 Feb 2015/1112bao, 10--13cm2.1599.5987.361.2818.4116.382.0
20 Feb 2015/1129bao, 20-23cm2.5089.5178.511.1416.5613.173.4
9 Mar 2015/1430ehs, 2--5cm16.477142.333127.7411.6721.9628.4-6.4
20 Apr 2015/1500ehs,4--7cm8.237+8.26081.960+60.94673.235+53.0561.8225.0129.47-4.5
20 Apr 2015/1500ehs, 9--12cm8.232+8.21471.380+74.50562.691+66.1091.9125.7228.20-2.5
20 Apr 2015/1500

ehs, 19–22cm

(not completely full, by about 2mm?)

8.265+2.13996.082+29.13385.418+25.465

1.63

(likely low)

21.5726.00-4.4

 

Note: Dry taken 23 Feb after air-drying in the lab for 3 days, then baking in the toaster oven for an hour.  (The oven got rid of about another 1.5g in each sample.)

The results show all EC5s about 2% low (which could be due to coupling to the soil, just after installation). 

Note2: 9 Mar sample processed as 2 aliquots (since scale range was limited).  The sum of both aliquots is shown in the above table.

Note3: 20 Apr sample also processed as 2 aliquots.  Both are shown above.

Note4: Tried to get a better depth match with 20 Apr samples, moving the 1cm ring to the top.

Note5: 20 Apr EC5 readings taken using minicom – see teardown comment.

Note6: assume that 9 Mar had a math error: 142.333, rather than 152.333???

 

tare = c(5.58, 2.15, 2.50, 16.477, 8.237+8.260, 8.232+8.214, 8.265+2.139)

wet = c(100.74, 99.59, 89.51, 142.333, 81.960+60.946, 71.380+74.505, 96.082+29.133)-tare

dry = c(83.54, 87.36, 78.51, 127.741, 73.235+53.056, 62.691+66.109, 85.418+25.465)-tare

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

rho = dry/vol

moist = (100*(wet-dry)/vol) # density numerically equal to volume mixing ratio since rho_water = 1.

ec5 = c(23.98, 16.38, 13.17, 28.4, 29.47, 28.20, 26.00)

matplot(moist,ec5,xlim=c(0,40),ylim=c(0,40)); abline(0,1,lty=2)

 

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