52 
AMERICAN POMOEOGICAE SOCIETY 
Our progress in irrigation in America has been largely along engineering 
lines. We have been interested in the establishment of irrigation systems; 
in the development of irrigation projects; in the building of expensive reser- 
voirs; and, it is well that we have done this, because it is the pioneer work 
in irrigation development. But what we need in the future is to study more 
the problem along horticultural lines. There is open to us a wonderful field 
of. experiment and investigation and as horticulturists we have a great re- 
sponsibility placed upon us to work out certain problems for the fruit grower 
who irrigates. 
In the first place, we should know how little water to use, rather than 
how much. The average man starting in irrigation has very little idea of 
the relative amount of water to use, usually acting on the principle that if 
a little is good a whole lot is better.. He seems to be possessed to use 
as much water as he can rather than to determine with how little he can get 
the desired results. 
A host of questions arises at this point, such as: What is the relation of 
this water to the fruit itself; to its size; to its color; to the form; to the 
yield; to the tendency to bear annual crops; to the vigor of the tree, and to 
its wood growth and foliage? What is its relation to the hardening of the 
tree in fall and winter? What is the relation to the maintenance of soil 
fertility? * 
In Oregon we have been trying to solve some of these problems. We 
have been working to determine the relation of a sufficient amount of mois- 
ture to these conditions. This desirable amount of moisture we control through 
means of irrigation. Some of the following observations that we have 
been able to make will be of interest: Whenever red apples, for example, 
suffer for water, their color is affected, in that they may take on a deep 
color, but it is a dead dull color. An ample supply of water means a bright, 
live, handsome color, which really sells the fruit. It does not seem to make 
much difference whether the lack of moisture comes from the lack of irriga- 
tion of from the lack of intensive tillage. Many of the same results can be 
obtained by the eastern fruit grower as can be obtained by the irrigator. 
One will control the moisture through irrigation, the other through proper 
soil management. When the trees suffer from lack of moisture 
the fruit is small. When the trees receive an ample water supply 
the fruit is large. I have often noted that fruit tends to be 
smaller on the old trees than it is on the younger, smaller and 
more vigorous trees. The form is very materially changed Apples which 
have plenty of moisture are more elongated and more angular, while when 
the trees suffer from want of moisture the product is round, flat apples. We 
see this same relation between fruits on young and old trees again. The 
young trees produce more elongated types and the older trees the round 
smooth type. It is largely a matter of moisture and food. The percentage 
of fruit that is free from blemish is larger where the trees receive sufficient 
moisture. There is less calyx cracking and splitting around the stem than 
is found where the ground is too dry. Then the size of the fruit is very 
materially affected. Much larger returns are realized where the tree has 
an ample moisture supply, and there is likewise a tendency to bear annual 
crops. Irrigation does not seem to affect the keeping or eating qualities of 
