INZ is currently producing a resource book on designing, installing, operating and managing fertigation in NZ – this will be available in Spring 2018
It is common for irrigators to apply effluent, fertiliser and agrichemicals through their irrigation systems in New Zealand. This is known as chemigation or fertigation. If correctly diluted effluent, fertiliser and agrichemicals can be very effectively, efficiently and safely applied by injecting them into water flowing through a properly engineered irrigation and injection system. INZ has produced an industry best practice guideline for the safe management of irrigation systems that have effluent, fertiliser and/or agrichemical injection.
New Zealand Guideline for the Safe Management of Irrigation Systems with Effluent, Fertiliser and/or Agrichemical Injection
This guideline is intended for designers and installers of irrigation systems with effluent, fertiliser and agrichemical injection. This may include engineers, equipment suppliers, and specialist irrigation designers. The design, installation and testing processes described in this guideline are intended to be applied to agricultural irrigation systems. The guidelines do not amend or replace other industry performance indicators, guidelines, codes of practice or standards. Designers and installers should interpret the guideline according to the requirements of individual properties and owners. All decisions made must also comply with statutes, regulations, and other legal requirements and industry standard
The guideline covers safe management practices and more specifically the recommended safety devices and systems to be used when injecting effluent, fertilisers, herbicides, pesticides and other agrichemicals into irrigation systems. It has been adapted from ASABE 409.1 MAR 1989 R2009. The guideline is not intended to replace backflow protection device recommendations for irrigation systems connected to a sanitary system in NZ. AS/NZS 2845 (2010) is the applicable standard for these scenarios. For irrigation systems where the water source is also used for rural drinking water the NZ Drinking Water standards may apply and impose conditions relating to hazards management.
Environment Canterbury have put together a guide to provide irrigators in the Canterbury region with information on chemigation valves for backflow prevention: Canterbury Backflow prevention Guidelines