une drop," i.e., the falling off of those fruits not well
enough pollinated or set to hold on to maturity. In thinning the fruit
should be taken off until they are not closer than from four to six
inches apart on the same branch, although the distance apart on any
branch will depend somewhat on the amount of the crop on other parts
of the tree. Never leave clusters of fruit on any branches, as some of
them are sure to be small and out of shape. Furthermore two apples
lying together afford a fine place for worms to get from one apple to
another and they seldom fail to improve the opportunity. Step ladders
and ordinary rung ladders are used to get at the fruit for thinning.
The cost of the operation is not nearly as large as might appear at
first thought and in practically all cases is a paying investment.

CHAPTER V

CULTIVATION AND COVER CROPPING

In its broad sense cultivation is the treatment of the soil. Thus
understood orchard cultivation includes the sod mulch system as well
as the stirring of the soil with various implements. In its more
common and restricted meaning, however, cultivation is the stirring of
the soil about plants to encourage growth and productivity. To have
the apple tree in sod was once the commonly accepted method of orchard
treatment--a method of neglect and of "letting well enough alone."
With the advent of more scientific apple culture the stirring of the
soil has come to be the more popular method. But within the last few
years an improved modification of the old sod method, known as the sod
"mulch" system, has attracted much attention because of the success
with which a few men have practiced it. For a correct understanding of
these practices and of the relative desirability of these systems we
must again turn to underlying principles and purposes.

It may be said on first thought that tillage is a practice contrary to
nature. But it accomplishes what nature does in another way. Tillage
has been practiced on other crops than trees for so long that we think
of it almost as a custom. There are, however, scientific and practical
reasons for tillage.

THE EFFECTS OF TILLAGE on the soil are three fold, physical, chemical,
and increasing of water holding capacity. Tillage affects the soil
physically by fining and deepening it, thus increasing the feeding
area of roots, and by bringing about the more free admission of air
warms and dries the soil, thus reducing extremes of temperature