THE CANADIAN HORTICULTURIST

Time of Application
In making a local test and also
in the general fertilization of
orchards, it appears that the time
of application is important. Our
knowledge on this point is not yet
as exact and definite as it should
be, but it now appears that one of
the principal functions of fertility
applications, in orchards is to fur-
nish available plant food early in
the season before the larger na-
tural supply in the soil is ready
for use.-Pennsylvania Agficul-
tural Experiment Station, Bulle-
tin 153.
pruning as it has been recommended in
this country is simply to defer growth
and prolong it later into the summer.
This practice has, therefore, an aspect
of serious danger and it would certainly
be unwise to'do any considerable amount
of pruning of any kind while the tree is
actively growing.
HOW FERTILIZERS ACT.
Stable manure is seldom used in dan-
gerous quantities on fruit trees except in
colder climates where winter killing is
likely to occur in any year. Where late
growth results it seems quite as likely
to be due in milder climates to lack of
lime as to excess of nitrogen. Fruit
trees, particularly plums, cherries, and
peaches, appear to require lime in abun-
dance, one of the chief effects of which is
to cause earlier ripening of the wood.
OTHER FACTORS
Orchard practice, with certain tender
fruits, as peaches, plums and cherries, is
very seriously complicated into the case
at this point. Too early maturity of
wood is not desirable, and is to be
avoided as carefully as is too late ma-
turity. The fruit grower, therefore, is
faced by the problem of balancing up all
the conditions which affect growth or
maturity in either direction. Too early
maturity is dangerous because thorough-
ly ripened wood starts into growth more
easily in mild weather in winter and is
much more likely to be injured by
colder weather coming after, especially
if the change from warm to cold should
be at all sudden. Thoroughly matured
fruit buds behave in the same way and
are likely to be destroyed by late winter
cold snaps or caught by early spring
frosts if they go into winter in an ad-
vanced condition.
THE USE OF FERTILIZERS
Studies of winter injury throw a par-
ticularly interesting light on the ques-
tion of tree nutrition and particularly
the use of fertilizers. Starved or neg-
lected trees suffer severely from winter

killing and there seems no room to doubt
that trees showing poor growth and
sickly color would be greatly improved
in health and in cold resistance by the
use of stable manure or nitrogen, the
lack of which is so plainly indicated.
There is abundant proof, also, that trees
which are allowed to exhaust their
energies in over-bearing are most sus-
ceptible to injuries of the kind under
discussion. This fact is important and
has several applications to fruit growing
practice which are decidedly far-reaching
in character.
One of the important means of pre-
venting exhaustion from over-bearing is
thinning of the newly-set fruit by hand.
It is perhaps riot too much to say that
thinning cannot be omitted if best
results are desired. Some peach growers
are able to do a 1arge part of the neces-
sary thinning at the time of the spring
pruning, but in any case it would prob-
ably pay well in the long run to go over
the trees when the fruit is well set and
see that the number and distribution of
fruits is satisfactory.
EFFECT OF PHOSPHORIC ACIDt
With respect to the use of fertilizers
it is probably true that phosphoric ac,*i
is more often deficient than any othr
element and since phosphoric acid is
known to have a very marked influence
on the nutrition of the general plant
body it is perhaps not too much to say
that a deficiency in the supply of this
elerient is more serious in its conse-
quences to the tree and to the grower's
pocket-book than any other fertilizing
constituent.
Lack of phosphoric acid is one of the
reasons for the common failure to set
fruit of trees which blossom very heavily.
The application of superphosphate to
induce fruit setting is in line with the use
made of this material by tomato growers
who make special application in liberal
quantity at the time of fruit setting.
PHOSPHORIC ACID
Phosphoric acid, with some plants,
has a stimulating effect on growth,
which is at first glance very similar to
that of nitrogen, but which on closer
study  proves very   different.   Phos-
phoric acid imparts a dark color to
foliage and a well developed, healthy
appearance to the entire tree. It plays
a very important part in the building up
of firm, well-ripened wood and even if
the growth is stimulated and corres-
pondingly late in maturing, the proba-
bility is that hardiness is increased
instead of diminished.
Reducing Fertilizing Costs
To reduce the cost of handling ferti-
lizing materials, the Ohio Experiment
Station officials are calling the attention
of farmers to the plan of buying acid
phosphate in bulk during the coming

spring. When shipped in bulk it may
be purchased for several dollars less per
ton and applied to the soil with practi-
cally the same amount of labor as when
handled in sacks.
Experiments show that acid phos-
phate may be applied with a fertilizer or
lime spreader any time after plowing and
before the spring crop is sown with good
results. When purchased in bulk the
acid phosphate may then be applied to
the soil when hauled from the railroad
station. In some cases the use of old
fertilizer sacks is recommended, the
sacking to be done at the car. The
sacks alone for a ton of fertilizer cost
from $1.50 to $3.
Small Fruits Being Planted
During the past three years there has
been a great increase in the plantiig of
small fruit and    the  trend of the
times indicates that this tendency will
continue indefinitely. One reason for
this is that besides the unusual ten-
dency toward a vegetarian diet brought
on by war-time garden development,
small fruits, such as strawberries, cur-
rants, gooseberries and grapes are being
substituted in many sections for tree
fruits. The smaller fruits are generally
cheaper, more easily grown, and fre-
quently more plentiful than the tree
fruits.
Cities depending upon 4 distant sec-
tion for small fruits nearly always receive
fruit of rather low quality, or at least
improperly ripened, because the fruit is
picked green. This condition has en-
couraged the development of home gar-
dens and small farms by city people, and
has led to the culture of small fruits
more than ever. Many land owners are
seeking to establish fruit gardens simply
to insure a good supply of highest
quality fruit for themselves. As a rule
the small fruits may be produced much
more cheaply than they can be pur-
chased upon city markets.
IMPROVING SOIL FERTILITYr
For the vigorous development of the
tree and an albundant crop of fruit, the
soil must contain the needed coinstitu-
ets in a more or less inanediately
available condition. It is for this rea-
son, as well as to replace the exhausted
plant food, that fertilizers are iieces-
sary to profitable apple growing. . . .
Soils differ so nuch in coipositioi that
.it is impossible to state definitely the
amounts of these fertilizers that should
be eimployed in all cases. . . . It may
be said that the best and most profit-
able crops can be obtained only when
the  soil contains   what  might be
thought to be a large amount of plant
food,  the greater part of which is more
or less assimilable.

58

March, 1919.