FOUR, 
NOT THREE, FOODS-DR. JENKINS. 
Vol. LVIII. No. 2564. 
NEW YORK, MARCH 18, 1899. 
81 PER YEAR. 
THE FEEDING OF A TREE. 
WHAT IT EATS. HOW IT EATS. 
Where Shall We Put Its Dinner? 
What Trees Contain. —We find in the substance 
of fruit trees, as in that of all other crops, consider¬ 
able quantities of potash, lime, magnesia, sulphuric 
and phosphoric acids, and relat¬ 
ively small amounts of soda, iron 
and chlorine. We have no data 
as to the total quantities by 
weight of these things in the 
whole tree, and we know that 
the different parts of the tree 
contain very different amounts. 
Thus the young wood contains a 
larger per cent of potash and 
phosphoric acid in the dry sub¬ 
stance than the old wood. Two 
years ago, I saved all the trim¬ 
mings from 16 yearling peach 
trees, and determined several fer¬ 
tilizer ingredients in them. I 
found in the dry twigs : 
Pounds per acre 
(150 trees) 
Nitrogen, 1.01 per cent.0.70 
Phos. acid, 21 per cent.0.14 
Potash, .47 per cent.0 33 
Lime, .97 per cent.0.68 
This, of course, represents only 
the growth which is cut off. We 
know that these things, although 
forming but a very small part of 
the whole tree, less than 1-40 of 
the twigs, less than 1-200 of the 
inner wood of the tree, are ab¬ 
solutely essential to the plant’s 
life. However small the total 
quantity, a certain amount is in¬ 
dispensable. 
Must Consider Lime.— 
There are four things—not three 
—which, generally speaking, the 
fruit grower has specially to look 
out for in his fertilizers—nitro¬ 
gen, phosphoric acid, potash and 
lime. The first three we need 
not say another word about, but 
why name lime with them ? Be¬ 
cause, for one thing, our Con¬ 
necticut soils, excepting a little 
in the western part, are not lime¬ 
stone soils, and are not rich in 
lime; although they may con¬ 
tain naturally more available 
lime than potash or phosphoric 
acid, yet it is quite likely that, 
unless care is taken, lime may be¬ 
come relatively deficient in fruit 
orchards. 
Then again, the growth of wood 
and of leaves of fruit trees makes 
much larger demands on the lime 
of the soil than on either other 
fertilizer ingredient. Thus the 
ashes of deciduous trees contain 
three times as much lime as pot¬ 
ash ; those of conifers nearly six 
times as much. The dispropor¬ 
tion between potash and lime is 
even greater in the case of leaves. On the other hand, 
most fruits contain more potash than lime. But the 
total annual growth of the tree, fruit included, takes, 
I believe, much more lime in the aggregate than of 
potash. 
Another reason for numbering lime with the ferti 
lizers to be applied to orchards is this : If any ingre¬ 
dient of the soil is lost by leaching, it is sure to be 
lime, and more of lime is likely to be lost in this way 
than of potash or any other mineral matter. We are 
told often enough that soils absorb or fix plant food, 
potash, ammonia and phosphoric acid, and hold them 
so that they will not, readily at least, leach out. We 
are not told, perhaps, often enough, that any fixing of 
these things is only possible by an unfixing, a releas¬ 
ing, of some other base—usually lime ; so that, if the 
soil is leached by rains at any time of the year, put¬ 
ting on potash salts, to a certain extent exhausts 
lime. Generally, perhaps, this loss is not a serious 
one, but on soils naturally poor in lime, it may be 
serious, and trees may suffer for want of lime, while 
they have abundance of the more expensive ingre¬ 
dients—potash and phosphoric acid. Nitrogen, phos¬ 
phoric acid, potash and lime, then, are the things 
which fruit-growers must regard in fertilizing or¬ 
chards. The other necessary elements of plant food 
will be supplied incidentally in supplying these. 
How the Tree Hats. —Next let us notice the way 
in which our fertilizers get into 
the tree. We know that, with¬ 
out exception, they must all come 
through the root system alone. 
The leaves do not, as some im¬ 
agine, take up nitrogen from the 
air. The root is the only way in. 
A large part of the dry matter of 
the plant to be sure, about 40 per 
cent, perhaps, is taken out of the 
carbonic acid of the air, by the 
leaves. But the mineral matter 
and nitrogen of the plant, which 
include our fertilizer constitu¬ 
ents, come to it only through the 
roots. It is worth while, then, 
to consider the way the roots 
grow, how far they grow, and 
how they get hold of plant food. 
It is a much more important mat¬ 
ter for orchardists than for those 
whose crops are of annual plants. 
With the latter, the fertilizer and 
the roots go in nearly at the same 
time, and the mistakes made one 
year can be remedied the next. 
But with trees, it is difficult or 
impossible to apply the fertilizers 
close to the living roots each year. 
All we can do is to feed them in 
a given place and let them come 
for their food, as animals do. 
With trees, two mistakes in the 
application of plant food may be 
longer in coming to light. All 
plants follow an orderly arrange¬ 
ment in the shape and growth of 
their root systems just as they do 
in their growth above ground. 
Wheat, barley and buckwheat, 
grown in a soil which is open, 
moist and evenly supplied with 
plant food, show just as marked 
and different characters in the 
way their roots grow and spread 
as are seen in the growth of their 
tops. 
How Roots Grow. —Some 
plants are naturally deep-rooted, 
some shallow, some have a strong 
taproot, others throw out several 
strong roots from the same point 
without a taproot. But while 
all this is true, it is likewise true 
that, in most eases, a tree or 
shrub cannot closely follow the 
architectural plan peculiar to it, 
but is forced by outside condi¬ 
tions to modify this plan. If the 
taproot strikes a ledge, it must 
turn aside, and being in this way 
made less effective, the lateral 
roots grow the more to take its place. If roots strike 
a stiff clay, and find too little air, they slacken or stop 
their growth there, and grow.the faster elsewhere. 
Hence, it is true, I think, of our orchards, that the 
shape and extent of the mass of roots are determined 
by tillage, character of soil, water supply and food 
supply, a great deal more than* , by*the J ll, nature of 
PENDULOUS NORWAY SPRUCE IN THE RURAL GROUNDS. 
See Page 204. 
Fig. 74 
