236 
and particles of earth that the roots 
would not penetrate unless broken up. 
For instance, a rock contains Many con- 
stituents necessary to plant growth, but 
as rock it is not available as food. Pul- 
verize the rock and moisten its particles 
and the roots will drink in their chemi- 
cals. The same is true of clods and of 
fertilizers. The breaking up, the eroding, 
the mixing of the harder substances un- 
til they are fully pulverized, render them 
soluble and make it possible for the roots 
to take their food in solution very much 
as human beings take food in the form 
of soup. 
Weeds—Weeds also absorb moisture, 
and because they compete with the trees 
for something to eat they should be de- 
stroyed and the food given to the trees. 
Irrigated Sections 
In irrigated districts, where abundant 
water is supplied, the question of mois- 
ture is not so important. However, irriga- 
tion does not pulverize the soil and does 
not keep down the weeds. In fact, it 
cannot be profitably substituted for culti- 
vation however much it may render un- 
necessary cultivation to conserve mois- 
ture. Our motto is, Drainage for wet 
lands and dust mulch for dry lands. 
Deep Plowing for Large Trees 
The question of deep plowing for large 
trees in the orchard has been a mooted 
question. We have taken both sides of 
this question. 
First, we favored deep plowing, think- 
ing that it would be better to turn under 
a coating of barnyard manure and throw 
up the hard sub-soil. We did this, and 
tore up so many of the little roots of 
the trees that we believed we had in- 
jured the orchard. It seemed to us im- 
possible for the tree to have its root 
system thus disturbed without injury. 
However, we had pruned rather heavily 
that year, and the breaking of the roots 
did not correspond in amount to the 
cutting away of the tops. We watched 
the trees carefully, and for the first year 
saw nothing to indicate that they had 
been either helped or injured. The sec- 
ond year they seemed to take on new 
vigor and the fruit was especially fine. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
This was doubtless due in part to the 
coating of barn yard manure, but we 
also think that the deep plowing where 
the soil is deep and the roots can pene. 
trate it easily may be beneficial. By 
observation in other orchards, we have 
reached the conclusion that when the 
surface roots are broken, generally the 
lower roots will sink more deeply into 
the sub-soil, and that deep plowing is a 
kind of root pruning. But often the roots 
will not get sufficient moisture at the 
greater depth, or the soil is so hard that 
they cannot penetrate, and more or less 
injury is done by deep plowing. The 
latest demonstrations have proven that 
a great percentage of the feeding rootlets 
are near the surface, and that most of 
them are from one to two feet in denth. 
The consensus of opinion is therefore 
shifting in the direction of shallow in- 
stead of deep cultivation for bearing or- 
chards. At this writing the question is 
a debatable one, and the probabilities 
are that in some cases it is helpful but 
in others injurious. (See Tree Roors ) 
Cover Crops 
What we have said in favor of cultiva- 
tion is not intended to disparage or to 
discourage the use of cover crops in or- 
chards. In fact, experience has shown 
that after an orchard has had clean cul- 
tivation until the trees are reaching the 
bearing period, the very best cultivation 
they can have, provided there is sufficient 
water, is the breaking up of the sub-soil 
by the strong vigorous roots of alfalfa. 
It is common for these roots to penetrate 
the soil to a depth of 25 feet, and in some 
places in a loose porous soil, as proven 
by the Arizona Experiment Station, they 
have gone to depth of 50 feet. They are 
much more vigorous than the roots of 
fruit trees, and in breaking up the hard 
sub-stratum, they lead the water to 
greater depth, and open up a new world 
of plant food for the roots of the trees. 
In the arid regions where irrigation is 
practiced, and where the soil lacks hu- 
mus, alfalfa, according to the best infor- 
mation available now, is the very best 
treatment for orchards set to apples and 
pears. 
