Page 23 - Landscape-Issue141(2)

IRRIGATION FEATURE

Inside a dripper Netafim dripline offer

comes down to: ones that are not intended for long-term be able to emit a pre-determined flow
• Soil type, composition, and behaviour use. HWD is more expensive than MWD, rate that is accurate and constant over its
• Crop requirements which in turn is more expensive than TWD. intended lifetime?
• Row and plant spacing PC drippers are more expensive than non-PC • Does the supplier comply with quality and
• System capabilities – maximum flow rate, drippers, and so forth.” industry standards?
pressures etc. As is clear from the selection factors • Does the supplier offer technical and
• Water availability. discussed in this article, a variety of drippers agronomic after-sales product support?
and driplines exist, covering a wide range of • Is the supplier reputable?
The most important aspect of this part of the crops and applications. The most suitable • Does the supplier have access to industry
dripline selection process is understanding option for the task at hand must be selected knowledge to support you in the selection
the way water moves in the soil on the one and will always come with a relevant price tag. and application of their product?
hand, and knowing the water requirements Neethling emphasises that dripper quality
of the crop on the other. The goal is to will of course have an impact on the y axis It is very important that the answers to
achieve optimal root zone management. (cost) of the dripline selection graph, but these questions are “yes”. An unfavourable
should not be added to the many factors answer to any of them can be the difference
Dripper and dripline duos included in the x axis of this graph. “Whether between irrigation success and failure in the
One aspect of a dripper’s specification is selecting thin wall or heavy wall drip, the field, despite having selected the seemingly
whether it is to be used in heavy, medium, most advanced dripper or one with fewer correct dripline.
or thin wall driplines (HWD, MWD or TWD). features, quality cannot be compromised.
“This ties in with required dripper longevity, It is possible to select quality products Holistic decision-making
listed under the factors to consider in while still maintaining the optimal balance The many factors that impact dripline
decision-making around technical dripper between drip irrigation performance and selection decisions cannot be viewed in
specifications and dripper features,” says equipment cost.” isolation. A holistic view of the planned
Neethling. “A big, advanced dripper meant Important questions you should ask farming endeavour is required, and all
to last a long time will logically be welded yourself when gauging dripline quality: aspects and how they impact one another
into a heavy wall dripline with suitable • Is sufficient technical data available? must be considered. The table below looks
durability. At the other end of the spectrum, • Considering the dripper filtration area at the interaction between production
a small dripper which holds greater clogging and turbulence coefficient, as well as the goals and conditions, and the many dripper
risk and is only purposed for short-term use, features of the dripline, will the dripline features and specifications.
will be welded into a thinner wall dripline.”
By this logic, long-term crop production will Factor Feature/Specification
require the use of big drippers in HWD. Short
term crop production will require drippers in Installation: Surface or sub-surface Flap outlet
Anti-siphon
TWD, while medium-term crops will require Root intrusion inhibitors
medium-sized drippers in MWD. It all boils Required system longevity (seasonal vs permanent drip) Size of the effective filtration area
down to what the crop and production Wall thickness
conditions require. Topography Pressure compensation
Cost, performance and quality ROI calculations (crop value and other impacting factors) All features and specifications
Quality considerations
Neethling urges irrigation designers and Possible production challenges Flap outlet
farmers to remember that equipment cost Anti-siphon
is a sliding scale determined by a host of Non-drainage
factors. Consider a dripline selection graph Root intrusion inhibitors
where the y axis is cost and the x axis is Crop water and nutrient requirements; Dripper flow rate
a composite of application, durability, Soil conditions, plant spacing, etc. Dripper spacing
clogging resistance and other factors
considered in dripline selection. “Naturally, Precision irrigation requires a system that is designed and installed with all resources and
movement along the x axis will result in production goals in mind, with the aim of ensuring optimal production.
movement along the y axis and the price will
increase or decrease. Larger, more advanced Text and images supplied by Netafim South Africa. This article was first published in the SABI
drippers are more expensive than smaller magazine, August/September 2024. n

Check us out www.salandscape.co.za Landscape SA • Issue 141 2024 21