Agriculture Reference
In-Depth Information
floor would be flooded for up to several hours at a time before the dams were
opened and the water allowed to flow out. While the trees received plenty of
water, root diseases and micronutrient disorders were also common, as was
soil erosion. The system required vast amounts of water and a perfectly level
orchard. In most areas today, flood irrigation for orchard crops is rare.
Sprinklers.
Sprinkler systems are an improvement over flood irrigation and
can be good choices for home orchards, as well as for commercial orchards
in areas where water is abundant and inexpensive. Sprinklers can be used
in orchards on sloping ground, they work well when you have alley and in-
row cover crops, and they are relatively simple to use. They can be set up to
automatically turn on at regular intervals or when soil moisture drops to a
specific level. Another plus is that you can easily spot a clogged sprinkler at
a distance.
Overhead sprinklers are sometimes used in home and commercial orchar-
ds to provide frost control for a short period of time. If temperatures drop to
around 34°F (1°C) and a damaging frost is expected, sprinklers are turned on
and are run continuously during subfreezing temperatures until the temper-
ature returns to above freezing. Although ice will form on the trees, as long
as there is a film of liquid water on the ice, the temperature of the ice and tis-
sues below it will remain at about 32°F (0°C), which will protect against frost
damage. This approach to frost protection is based on the nature of water to
release heat as it changes from liquid to solid.
If you use sprinklers for frost control, you will need to cover the trees
completely with water and apply at least
⁄
4
inch of water per hour for as
1
long as there is a risk of frost. These systems work best for short-term frosts
that last a few hours. They are not effective against masses of freezing air
that settle into orchards for several days.
