Ditches for Lrrigation. ; 173 
the fullest activity on the part of the tree. Irrigated ground not 
properly treated becomes compacted, fissured, cloddy and gen- 
erally hateful, losing moisture rapidly, setting around the roots 
like cement and tearing them by its subsequent shrinkage. 
These conditions do not occur on the lighter soils, and yet even 
these are best when cultivated in a rational manner. 
METHODS OF IRRIGATION. 
There are various methods employed in California for the 
conveyance and application of water to trees and vines. Some 
of the principal ones may be enumerated and described as 
follows :—- 
Permanent Ditches —Permanent runways for water are be- 
coming far less popular than they were in earlier days, because 
it is seen that the trees thrive far better if cultivated. There is, 
however, on hill lands difficult to plow and cultivate, and prone 
to wash, a naturally strong temptation to lay out the ditches once 
for all on grades suitable for slow running of the water, and 
trust to seepage and percolation from these ditches to supply 
moisture to the trees adjacent to them. By this method irriga- 
tion must be more frequent than by other methods which will be 
described, because the soil is not so well saturated, and even the 
more frequent application takes less water than less frequent 
application through newly-turned furrows. There is, also, neces- 
sity for much work with the hoe if the grower pretends to keep 
down the weeds—which,. however, is not always done, and the 
running water distributes the seeds. 
Annual Ditches —A modification of this method, which pre- 
vails to some extent in the foot-hills, consists in giving the or- 
chard a thorough plowing when the heavy rains are over in the 
spring, plowing under the winter growth. The surface is kept 
stirred after later showers. In May shallow ditches are made 
with a double-moldboard plow nearly along contour lines, which 
are quickly located with a level. Slight fall is given so the water 
will flow slowly, and these ditches are used all during that season, 
and allowed to remain to carry down winter water until the next 
thorough working in the following spring. This plan makes 
summer cultivation somewhat difficult, but it may be the best 
method on the sharp foot-hill slopes. 
Large ditches are also used between the rows of bearing 
trees on level land in soils which readily absorb water and the 
roots are widely extended. It is chiefly used on lands adjacent 
to rivers, from which water is pumped in large volume. For 
example, along the Sacramento River, on land that is apt to bake 
by flooding, or by the large check system, soon to be described, 
large ditches are plowed out in the centers between the tree rows 
