Soil Management Handbook - Ministry of Agriculture and Lands

Impact of large drops of water disperses soil particles
and leads to compaction. Nozzles should be chosen
to discharge water in small droplets. Also, soils that
have been wetted by irrigation are more vulnerable to
compaction from traffic.
With the increased demand on a limited supply of
water in the Okanagan and Similkameen Valleys,
trickle or drip irrigation systems have become
popular. Trickle systems can deliver water to crops
more efficiently than sprinkler systems, although, the
level of system design and maintenance is greater.
Trickle systems should be designed to match the
anticipated peak evapotranspiration rate of the crop.
The system should be designed to operate for not
more than 20 hrs/day. Trickle irrigation systems are
described in the publication, B.C. Trickle Irrigation
Manual.
Trickle irrigation systems offer additional benefits to
sprinkler systems in applying nutrients and systemic
pesticides. As water is applied directly to the plant's
root zone, nutrients can be efficiently applied. Trickle
systems may not be compatible with herbicides or
insecticides as the chemical is not applied evenly over
the entire ground surface. An exception would be
spray emitter systems which could be used for weed
control on some crops. At the present time, there are
no chemicals registered for this type of use.
Injection systems are required for maintenance of the
trickle system. The addition of chlorine and acids to a
trickle system may be required in some areas to
prevent algae and precipitate buildup in the emitters
and lateral lines.
Chemigation
Chemigation is the term used to define the practice of
applying chemicals to a crop through an irrigation
system. Chemigation, includes fertigation, but also
applies to the application of pesticides and growth
regulators. The goal of a chemigation system is to
apply the proper amount of chemical to the target area
in a safe, efficient and uniform manner. The
following precautions must be taken to achieve this
goal:
• assure personal protection,
• be aware of the danger to the environment,
• calibrate the injection equipment to apply the
correct amount of chemical at the right time and
in the correct concentration, and
• use a well designed and maintained irrigation
system.
Advantages of Chemigation
The application of chemicals through an irrigation
system offers many advantages to the producer.
Advantages obtained depend on the type of irrigation
system used and type of chemical applied.
• Reduces the cost of chemical application by up to
50%.
• Reduces energy consumption by up to 90%.
• Insures timely application of chemicals.
• Reduces chemical use. Studies have shown that
less fertilizer or pesticide is required when
applied more efficiently.
• Reduces labour costs.
• Reduces machinery equipment needs.
• Improves operator safety. Exposure of the
operator to chemicals applied through an
irrigation system is greatly reduced.
• Improves crop production by simplifying cultural
practices and improving crop production and
quality if used correctly.
Disadvantages of Chemigation
Chemigation is not viable for all chemicals.
Chemicals may not be soluble or remain in solution or
may not act as intended under an irrigation
application regime. More than one method of
chemical application should be retained.
• Specified use and application according to
product label. Pesticide labelling and/or
registration restrict application techniques.
• Requires the addition of safety equipment. To
prevent the possibility of backpressure or
backsiphonage into a potable water source,
approved cross connection control equipment
must be installed and proper procedures followed.
• Requires an increase in system management.
Personnel in charge of the chemical application
must fully understand the calibration of injection
52 Soil Management Handbook – Okanagan-Similkameen Valleys