CHAPTER XY, 
IRRIGATION OF FRUIT TREES AND VINES. 
Whether fruit shall be grown with irrigation or not is a local 
and specific question, and it must be answered with due regard 
for several conditions, among which are: First, the minimum 
local rainfall; second, the character of the soil and subsoil; third, 
the situation and environment of the ground on which the fruit 
is to be grown; fourth, the kind of fruit which it is desired to 
produce. 
These conditions are all correlated, and a knowledge of 
them all is necessary to an intelligent decision as to correct prac- 
tise in any given locality. For example, the amount of rainfall 
which is adequate in one locality, or in one situation, even, may 
be quite insufficient in another, because, first, one soil may be 
deep and fairly retentive, into which roots can penetrate and find 
abundant moisture; second, another soil may have sufficient 
depth, but be so porous as to lose its moisture by evaporation, 
or so leachy as to lose it by drainage; third, still another may be 
shallow, and quickly dried out under a fervid sun, or quickly 
drained by reason of a sloping substratum of rock or hard-pan, 
while another similar soil, differently situated, may receive abund- 
ant moisture from the drainage of the slope above it; fourth, 
possibly in all the soils cited there might be adequate moisture 
for deciduous fruits, but citrus fruits would require irrigation; or 
enough for young, but not for bearing trees. : 
Thus it appears that even to decide whether a location has 
sufficient rainfall for the growth of fruit without irrigation, one 
must pass judgment upon all the conditions first mentioned. It 
is hardly worth while, then, to discuss such a topic upon theoret- 
ica lgrounds, or to attempt to answer the general question, Shall 
irrigation be employed in the growth of fruit? The true guide 
is enlightened local experience, and the true test is the growth 
of the tree and the excellence of its fruit. So long as the grower 
is able to secure every year a generous amount of good-sized 
and excellent fruit by natural rainfall, he need concern himself 
very little about irrigation; if his tree shows distress, and his 
fruit, even when properly thinned out, is not up to market stand- 
ards every year, he may do well to provide himself with irriga- 
tion facilities, either for constant use or to supplement rainfall 
when it is occasionally deficient. 
( 167 ) 
