Effective spray application starts with more than the right chemical, sprayer and nozzle set-up – water quality can also influence spray performance.
Water quality varies depending on its source and can change throughout the year, particularly after heavy rainfall or drought. Poor water quality can:
- reduce the activity or solubility of some chemicals
- block spray lines and nozzles, affecting application uniformity
- increase wear on nozzles and spray equipment.
Testing your spray water can help identify issues before they affect application. Water should be tested for pH, salinity and hardness, and where relevant, sodium adsorption ratio (SAR).
Collecting a water sample
For an accurate assessment of your spray water:
- Use a clean container with a capacity of at least 500 mL.
- Rinse the container at least four times with the water being sampled.
- Fill the container completely, leaving no airspace, seal it tightly and label it as required by the testing laboratory.
Bore water: For a new bore, run the pump for several hours before taking a sample. For an established bore, allow it to run for around 30 minutes before collecting the sample as close to the bore as practical.
Dam water: Take the sample away from the water’s edge and close to the pump suction inlet. Dam water can form distinct layers, so consider whether these need to be sampled separately or the water mixed before sampling. Water should also be filtered to remove organic matter.