318 
ments are not in the soil in available 
form they must be applied. It is not only 
necessary that they be present in the 
soil, but they must be in a soluble form, 
for in such form only can plants make 
use of them. Some kinds of fertilizers 
dissolve readily when applied to the soil. 
There are other kinds that become avail- 
able gradually and some others that are 
so nearly insoluble that most plants can- 
not make use of them. The apple, being 
a long lived crop, can make use of the 
slow working fertilizers, but the tendency 
among careful apple growers is to use Ssol- 
uble fertilizers and apply them just when 
needed. The experienced apple grower 
who keeps a close watch of his trees will 
probably get best results from soluble fer- 
tilizers, but the average farmer will do 
well to adhere to the use of fertilizers 
that become available gradually. 
C. D. JARVIS. 
Storrs, Conn. 
Bearing Orchards 
The fertilizing of bearing orchards sel- 
dom receives adequate attention. Bear- 
ing trees in the crops removed make 
heavy. drafts on the elements of plant 
food in the soil. The most important 
elements which are removed are nitro- 
gen, potash, and phosphoric acid. Rob- 
erts*, in an experimental study of the 
question, found that allowing 35 trees 
to an acre, and a yield of 15 bushels to 
a tree, the plant food removed in 20 
crops of apples, and the leaves for the 
same period amounted in round numbers 
to 1,337 pounds of nitrogen, 310 pounds 
of phosphoric acid, and 1,895 pounds of 
potash. Comparing the amounts used 
with those required by ordinary wheat 
crops (15 bushels per acre and 35 pounds 
of straw), for an equal length of time, 
the apples removed practically three 
times the quantity of potash, half again 
as much phosphoric acid, and twice as 
much nitrogen. 
The roots of a tree are constantly ex- 
tending over a larger area, but it is plain 
that if we would maintain our trees in 
the best condition and improve the aver- 
* Roberts, “Soil Depletion in Respect to the 
Care of Trees.” Cornell Experiment Station 
Bulletin 108. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
age Size of fruit from year to year, we 
cannot neglect attention to this matter 
The tendency of increased feeding, es- 
pecially in connection with thinning of 
the fruit, would be to do away with “off 
years,” and reduce the damage due to 
insects and fungi. It is a noticeable fact 
that vigorous trees do not suffer from 
the attacks of these organisms as much 
as those which have been more or less 
enfeebled from some unfavorable condi- 
tion or circumstance. In good soils trees 
will get along for some years, but after 
bearing begins it is only a few years 
before the trees will begin to feel the 
need of plant food to compensate for that 
removed. Of these nitrogen is most 
cheaply supplied by means of good tillage 
and the judicious use of green manures, 
like cowpeas, and winter covers of vetch 
and rye. Diminished growth and pale- 
ness in the color of foliage are to a con- 
siderable extent guides in determining 
the need of nitrogen. Frequently too 
much dependence is placed on the vir- 
tues of legumes to the exclusion of appli- 
cations of other fertilizers. Excess of 
nitrogen should be avoided. There should 
be a balanced “ration.” In the case of 
bearing trees applications of potash are 
ealled for; also of phosphoric acid. Cow- 
peas do not increase the supply of these 
elements as they do of nitrogen. 
Stable Manures 
Practical men report excellent results 
from the use of stable manures. There 
is no objection to their reasonable use on 
apples. Commercial fertilizers may sup- 
ply the same manurial elements in less 
bulk and with relatively greater profit. 
But especially on the lighter soils humus 
is needed, so it is well to make use of all 
the methods of supplying the elements 
needed. A good plan would be to let 
an application of stable manure—-20 to 
25 tons per acre—take the place of leg- 
umes once in four or five years. Whether 
the leguminous crops are kept up annu- 
ally in the interval will depend on the 
needs of the trees. An application of 
50 to 100 pounds of nitrate of soda per 
acre just before the growing season might 
be desirable under conditioris where there 
