4) Gypsum block installation

• Layout four adjacent holes as illustrated
• Installation
  • soak gypsum block (~5 min)
  • auger to 10 cm
  • make mudball, throw down hole
  • push gypsum block into mud
  • backfill hole completely, place PVC collar
  • check with meter
  • tell them to repeat for 30, 60, 90 cm

5) Gypsum block calibration

• Calibration can take months
• Requires that your soil goes through one or two complete dry-down cycles
• Make meter observations regularly
• Every time your meter reading changes 5-10%, collect a calibration sample from 30 cm (also 10 cm, time permitting)
  • follow step 3 under "Gravimetric" protocol
  • calculate Soil Water Content
• Plot meter reading using x-axis scale and soil water content using y-axis scale
• Repeat 10-20 times
• Should recheck every 6 months
• If your soil does not dry out, watch for lab calibration procedure at:
  http://www.hwr.arizona.edu/globe/globe_home.html