Clearwater Republican. [volume] (Orofino, Idaho) 1912-1922, 1922-03-31
Extension Horticulturist, Oregon
Agricultural College.
BY Clayton L. Long,

In order to comprehend FULLY the
fertility problem as related to orchard
| ing, it is well to consider the extent
and sources of losses of fertility from
orchard Soils for it is recognized that
for continued profitable fruit produc-
ton and constant maintenance Of soil
! fertility it is necessary to return to
the soil as much fertility as is removed
| by the various agencies at work. These
and teaching, and oxidation of nitrogen
and organic matter.
Losses by Crops Removed.
Fertility removed annually per acre
by an apple orchard.
Annual weight Wood: $500 lbs. !;
leaves, $500 lbs; fruit, 24,5O0 lbs to-
tai. 1900 lbs.
Nitrogen-Wood, 11.3 lbs; leaves,
356 lbs; fruit, 1862 lbs; total, 531 lbs
Phosphoric acid Wood, 36 lbs !;
leaves, So lbs; fruit, GA lbs; total,
1873 lbs.
Potash-Wood, Sc lbs; leaves, 1853
lbs; fruit, Ais lbs; total. $40 lbs.
The above shows that an acre of Wig
orous, producing apple trees removes
nitrogen equal to that carried by $40
pounds of nitrate of soda Phosphoric
acid equal to that carried by 95 pounds
of Is per cent super-phosphate and
potash equal to that carried by 1876
pounds of sulfate of potash Gener-
ally speaking one acre of apples does
not remove as much nitrogen as an
equal area of ordinary farm crops,
about the same amount of phosphoric
acid and considerable more potash.
Losses by Drainage and Leaching.
If the fertility removed by the trees
constituted the total loss the problem
would not be so difficult but there are
losses through other channels as we'll
Fertility existing in soluble form is
liable to be lost in drainage water or
by teaching down through the subsoil
beyond the feeding roots. The amount
4ost in this way depends upon the
amount of soluble fertility, the nature
of the subsoil and the amount of rain
fall. The heavy rainfall and the mild,
open winters of western Oregon are
conditions ideal for such losses, and
undoubtedly contribute greatly to the
deterioration of these soils. The most
serious loss from this cause is that of
nitrogen. This is the most deficient
OF the three key elements in our or
chard soils, especially where clean cul-
tivation without annual cover crops
or manuring has been practiced. 1t is
also the most expensive to supply,
costing in commercial forms about 20
cents pound. Experiments made at
Rothamsted, England, upon productive
land, with an average rainfall of 28. O2
inches and an estimated drainage of
10 inches, resulted in a loss of more
than IS pounds of nitrogen, equivalent
to that carried in 225 pounds of nitrate
of soda. With the much greater rain.
fall of western Oregon. drainage from
these soils would be even greater.
Phosphorus lost by drainage is gen.
orally conceded to be small, as little
of it exists in soluble form at any time.
Potassium is lost in greater amounts
although not equalling the loss of nitro.
gen. The fruit soils contain large
amounts of this element, but practical.
ly all of it exists in an. insoluble form:
hence, the loss of even a part of the
soluble amount is of vital significance
to the grower.
Another important source of loss is
through the decay or oxidation of the
matter of the soil. This pro.
cess consists in combination of the
substances of the organic matter and
the oxygen of the air. Most of the
compounds formed are gases and pass
on into the air. The more contact
there is with the air the more rand
decay or oxidation proceeds. The or.
ganic matter carries practically all the
nitrogen of the soil. hence this process
affects the nitrogen of the
SOIL. Clean cultivation and exposure
OF the soil to the air and rays of the
sun hastens this process. The extent
OF this loss has never been fully de.
'os thcit Cdn ne no doubt
but that it is very large.
Probable Losses Of Fertility Annually.
After all practical precautions have
been taken to check the losses of fer.
tility from the soil it will be found
that large losses still occur. The Min
nesota experiment station after max.
ing several tests, concludes that from
three to five times as much nitrogen is
lost from the soil annually as is re.
moved by crops.
The Canadians found that by %
years OF grain farming, practically one.
third of the nitrogen of their soils to
depth of eight inches was lost.
There is no investigation known to
the writer which indicate the total
loss of fertility in fruit growing and
1t Is more or less hazardous to make
an estimate. Taking everything into
however, it will certain.
ly be within the facts to assume that
where apples are grown under clean
cultivation, there is an average an.
nual loss of 200 pounds of nitrogen
20 pounds of nhospho rn, 81 ~