izers
give but medium results.

ELEMENTS OF FERTILITY.--Three elements are necessary for the growth of
apple trees, nitrogen, phosphoric acid, and potash. To these lime may
be added, although its benefit is indirect rather than direct as a
plant food. How badly any of these elements may be needed depends on
the soil, its previous treatment, and on the system of management. By
learning what are the effects of these elements on the tree and fruit
we may determine under what conditions, if any, their use is
advisable.

Nitrogen promotes the growth of new wood and leaves, giving the latter
a dark green color. In fact the color of the leaves and the amount of
the wood growth are usually good indicators of the need of nitrogen.
Nitrogen in excess develops over vigorous growth and prevents the
maturity of wood and buds. It always has a tendency to delay the
maturity of the fruit by keeping it growing late. On many varieties it
tends to produce poorly colored fruits.

When trees are making a normal amount of growth in a year--say a foot
to three feet or more--and when the leaves are of good size and a
dark green in color, there is little need of nitrogen. But when trees
are not growing satisfactorily and the leaves have a sickly yellow
color, then the need of nitrogen is evident. On early soils and in
long growing seasons nitrogen may be more freely and safely used than
under other conditions.

The effect of phosphoric acid and potash on the tree and fruit is much
more uncertain. They are supposed to influence the quality and the
flavor of the fruit, giving better color and flavor, and this they
undoubtedly do to some extent. Potash probably gives the leaves a
darker green color. The precise effect of these two elements is at
present a subject of much discussion, one set of investigators
maintaining after a long and careful investigation that these effects
are too small to be worth while, and the other claiming that they have
a marked effect in the ways above indicated. The only safe guide is
the actual local result. If the fruit is satisfactory in every way it
will be of little use to try fertilizers. On the other hand, if it is
not, then it will pay to experiment with them. The needs of and the
results on different soils are so variable that it is always wise to
experiment on a small scale before using fertilizers extensively.

STABLE MANURE.--The necessary plant food is best supplied by stable
manure applied at the ra