Many kinds of material ranging from paper to glass wool have been used
as mulches for fruit trees, discloses J. H. Gourley, of the Department
of Horticulture at The Ohio Agricultural Experiment Station. Straw, hay,
and orchard mowings have been most commonly used.
In some areas, sawdust and shavings are available in quantity and have
been used to some extent for mulches which raises the questions of
whether they make the soil acid.
The Experiment Station has used both hardwood and pine sawdust and also
shavings for a number of years in contrast with wheat straw, alfalfa,
timothy, and others. No difference in appearance or behavior of the
trees can be noted. Sawdust packs and gives poorer aeration than straw
and it requires a large amount to mulch a tree. This mass also absorbs a
large amount of rainfall before passing through to the soil but no
injurious effects have been noted.
The chief question has been about soil acidity and it may be stated that
after 12 years of treatment the soil is little or no more acid than it
is under bluegrass sod. The soil under the latter has a pH of 5.22, the
hardwood sawdust 5.07, the softwood sawdust 5.07, hardwood shavings
5.20, and wheat straw 5.35. Contrary to the common conception, no
objection to sawdust from the standpoint of soil acidity is justified
from Station experience.
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