www.arborage.com Arbor Age / June 2014 9
and Dump" site had been prepared, the better the organic
matter, bulk density, and microorganism picture would be.
But a graduate student, Miles Sax, tested the various gardens
around campus that had all been prepared in the same way, and
found that the result was just the opposite. "The longer ago
we put in the garden, the more organic matter was in the soil
and the lower the bulk density," said Bassuk.
Her hypothesis is that the large quantity of compost that
was initially placed on the site was enough to get the bacteria
and fungi in the soil cooking and multiplying. Then it appears
that those microorganisms were suffi ciently numerous to be
able to use the bark mulch as food, bringing it down to lower
levels in the soil, where byproducts are available as plant nutri-
tion and aid in creating desirable soil aggregates.
"We're excited about this," said Bassuk, "because it tells us
that the value of that initial soil remediation, that simple Scoop
and Dump, is huge — it really pays off. Arborists: sell your cli-
ents on soil preparation for their compacted soils. If that effort
is made on the front end, all that has to be done in subsequent
years is to replenish a light layer of bark mulch."
Michelle Sutton (michellejudysutton.com) is a horticulturist, writer
and editor.
Scoop and Dump in action.
