Consider water quality before spray operations

image of sprayer
Growers and spray operators are encouraged to test water quality before using it for the application of herbicides and pesticides this season. Photo: Evan Collis Photography.

Western Australian grain growers and spray operators are encouraged to test water quality before using it for the application of herbicides and pesticides this season.

Grain Research and Development Corporation (GRDC) crop protection manager – west, Georgia Megirian, said recent dry conditions had reduced the quality of water available for in-season spraying operations in many areas of the WA grainbelt.

“Poor water quality can adversely impact the results for many farm chemicals,” Ms Megirian said.

“Along with consideration of the target, it is equally important to consider water quality when determining product choice, rates and the optimal water rate as directed by the label.

“This will help to ensure the most effective result is achieved, and the best return for product investment.”

Ms Megirian advised growers and spray operators to always consult product labels and the manufacturer’s technical information about water quality requirements, and to test water regularly.

“If using bore water or water sourced from the ground, it is recommended that a full laboratory test is obtained annually,” she said.

“Dam water and tank water should also be tested annually.

“If extending the interval between tests to two years, use test strips to check water quality in between testing.

“If a significant change in pH or hardness is noticed on the test strips, get the water retested by a laboratory.”

Ms Megirian said the GRDC Spray Water Quality Fact Sheet, available on the GRDC Spray Drift web page, contained information about water testing, including what should be measured and how to address any issues identified through testing.

“Water tests should analyse the following: pH, total hardness (including a measure of bi-carbonate levels) and total dissolved salts or salinity,” she said.

The fact sheet is just one of many resources available to help ensure that spray systems are operating to their full potential and in accordance with regulations.

GRDC senior manager biosecurity and regulation, Ken Young said a range of resources were now available on the GRDC Spray Drift web page, to support growers and spray operators with the very latest best practice advice and guidance.

“Spray application is an integral activity in grain operations and one that requires careful planning, preparation and implementation,” Dr Young said.

“The GRDC Spray Drift web page offers guidelines about how to mitigate spray drift risk, weather implications in spray application, nozzle selection, application and equipment, and State and Territory-regulatory contacts.

“It also has information about how to comply with changes, recently implemented by the Australian Pesticides and Veterinary Medicines Authority (APVMA), to the application requirements of 2,4-D herbicides.”

Revised and recently developed GRDC resources available on the GRDC Spray Drift web page, in addition to the Spray Water Quality Fact Sheet, include:

  • GRDC Spray Application Manual
  • Fact Sheet: Maintaining Efficacy with Larger Droplets – New 2,4-D Application Requirements
  • Fact Sheet: Pulse Width Nodulation: Nozzle Selection Guide
  • Fact Sheet: Spraying Efficiency
  • And the latest Nozzle Selection Guide.

The web page also includes a six-part GRDC Spray Application video series, featuring spray specialist Bill Gordon, discussing a range of topics including:

  • 2,4-D label changes
  • A spray contractor’s experience managing spray drift
  • Maximising spray coverage
  • Maximising spray efficiency
  • Nozzle selection for larger droplets
  • Weather conditions and the 2,4-D label.

Other industry resources with information about the new APVMA instructions and how to mitigate spray drift risk are available at:

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