The following physicochemical characteristics were measured
for each substrate combination: soil texture, soil stability, pH
(Multiline P4 universal meter), and organic matter content. The soil
texture was determined as follows. The substrate material was
finely pulverised and put into a glass jar until it was 1/4 filled, to
which water was added until it was 3/4 filled. One teaspoon of
powdered, non-foaming detergent (Spraynex, Environex
International) was added to the jar, which was then covered tightly
and shaken vigorously to allow the soil aggregates to break apart.
The jars were left undisturbed for 3 days to allow the different particles
to settle, after which the thickness of each layer was measured
(i.e., sand, silt, clay, and total deposit) and the percentage