taken by pressing a sharpened stainless-steel cylinder (5 cm inner
diameter and 5 cm height, 100 cm3 volume; Eijkelkamp, Netherlands)
into the soil. Twelve to fifteen samples were taken along the parallel
transect (depending on tree spacing) and six along the perpendicular
transects, three on each side of the parallel transects. Dry leaves,
stems and other vegetal residuals on the soil surface were gently removed
by hand prior to sampling.
After pulling the cylinders out of the soil, the upper and lower cylinder
faces were immediately sealed with fitted plastic caps to prevent
changes in soil water content and exposure of the soil surface to air.
The soil samples were stored in the laboratory in special aluminum
cases that were resistant to humidity and heat (Eijkelkamp) until the
SWR determination in the laboratory. The upper plastic cap of the cylinders
was removed prior to the WDPT measurements and the cylinders
were kept under standard laboratory conditions (23 °C and ~50% relative
humidity) for a several days to obtain uniform moisture content
distribution along the length of the cylinder. This process was repeated
for all samples to neutralize the effect of differences in field moisture
content.
Soil samples were taken from the 0–10 cm layer of the three Revivim
plots (RM0, RM1, RM2), air-dried, sieved (N0.5 mm) and packed in a
consistent manner in a container of 12 cm radius and 21.85 cm height.
These soil samples were used for infiltration measurements by discinfiltrometer
(Section 2.3.3).