The Canadian Horticulturist and

(See Pages 67-72)

Beekeeper
TORONTO, MARCH, 1919

Vol. 27

(See Pages 67-72)
No. 3

The Relation of Winter Injury to Soil Fertility*
Prof. J. W. Crow, O.A.C., Guelph, Ont.

ONE does not require to trace the
history of fruit growing in On-
tario very far back in order to
reach the conclusion that our climate is
subject to dangerous extremes and that
many of our orchard practices require to
be carefully examined in the light of the
test conditions which are certain to
occur. Fruit trees in our climate are
subject to serious risk and from time to
time losses occur the extent of which is
seldom fully appreciated. It is prob-
ably safe to say that the extremely severe
winter of 1917-18 imposed upon the
general fruit growing interests of this
province a disability in excess of 25%.
Some would rate the damage much
higher-up to 30 or 40%, but in any case
it is extremely serious. With farm crops
a loss of this magnitude would be en-
tirely made up in a year or two by in-
creasing acreage, but in fruit trees the
matter is not so easily rectified. The
damage inflicted is permanent and is, in
effect, repeated annually up to the life
time of existing plantations. Add to
this the fact that the lifetime of most
trees is appreciably shortened by even
one such winter and it becomes apparent
*Extract from an address delivered at the
recent annual convention of the Niagara Pen-
insula Fruit Growers' Association at St. Cath-
arines.

that the sum total of the injury could
only be offset by the planting of a very
large number of trees. It is safe to say
that of every 100 trees set in commercial
orchards not more than 50 come into
bearing, which means that in order to
offset as fully as possible the damage
done last year it would be necessary to
plant two young trees for every mature
tree killed. If we estimate the losses at
25% this means that an acreage of
orchard would require to be set which
would be equal to half the acreage now
in existence. We all know that such
extensive planting is not likely to occur
but the figures given will serve at least
to bring out the seriousness of the
situation.
In observing the effect of last winter
upon trees, it becomes obvious at once
that the particular treatment given has
an important relation to the amount of
injury experienced. We are all familiar
with the fact that late growth of trees is
dangerous, but it would perhaps do no
harm to sum up the several influences
which may cause growth to continue to a
dangerously late period.
The effect of late tillage is obvious. It
stimulates root activity directly, by
aeration and indirectly by increasing
bacterial action, thereby liberating plant

foods. Late tillage also tends to keep
the land warm and in this connection
mention should be made also of autumn
or fall plowing. If plowing is done too
early the effect is to stimulate root
action by preventing the natural cooling
process which ordinarily checks root
activity. It is a well known fact, too,
that growth is later on wet land or in
seasons of heavy fall rains. The reason
in both cases is because the high water
content keeps the land warm and the
roots correspondingly active. Thorough
drainage is essential for fruit trees, as
was well demonstrated in this locality
during the excessively wet June of 1917.
Peach and cherry trees in low ground
were killed outright by the wet, which
occurrence is most significant in spite of
its rarity.
EFFECT OF PRUNING
Too heavy pruning in the dormant
season may stimulate growtlt beyond
the point of normal maturity as may
also summer pruning or pruning done
when the tree is actively growing.
Repeated cutting or pinching in the
growing season as carried on in European
practice may possibly check growth
somewhat, as it is said to do, but the
customary result of ordinary summer;

In British Columbia fruit growers show a greater disposition than is shown by fruit growers in Eastern Canada to use fertilizers in their orchards
and gardens and phenomenal yields are sometimes recorded. An orchard scene in the Rutland District near Kelowna, B. C., is here shown.