TESTING all water supplies so they can be ranked according to suitability is critical before spraying as poor water quality can adversely affect many agri-chemical products.
Independent agronomist and spray application specialist Bill Campbell said there were two main ways agri-chemical products can be affected.
"The first impact is loss of efficacy or performance, which is primarily around glyphosate and paraquat, and the other impact, especially when it comes to salty water, is compatibility or tank mix instability," Mr Campbell said.
"Always consult product labels and the manufacturer's technical information about water quality requirements for the product and formulation type."
While the importance of water testing has been spoken about for a long time, there are areas in the Great Southern that are desperately short on water, meaning farmers are using bore water and dam water for the first time in a long time.
Water testing should be done on a regular basis, at least every 12 months, when using bore or dam water, reticulated (piped) water sources, and water stored in concrete tanks.
"With bore water in particular, it needs to be tested once they're in use, not when they're static or haven't been used in a while," Mr Campbell said.
"In order to be useful, all water supplies should be analysed for pH, total hardness (including a measure of bi-carbonate levels), total dissolved solids/salts, and salinity (electrical conductivity).
"It is recommended to use a suitable laboratory that specialises in water quality testing for agri-chemicals and can provide suitable prescriptions in relation to."
By testing all water supplies, they can be ranked from best to worst by looking at the factors that are affecting them.
Whereas if only one supply is tested and it's not suitable, it is necessary to go back and check the others anyway.
"There are limitations to a simple test strip - it will tell you if the water quality is alright, but if it's bad and exceeds the capacity of that test strip, then it doesn't provide you with any more information," Mr Campbell said.
"My recommendation is always to send a water sample away to be tested, that way growers receive a comprehensive analysis and have all the information that is needed to make a decision."
After a full analysis has been completed, simple test strips can then be used to assess if significant changes in water quality have occurred and when a more comprehensive laboratory test may be required.
"It is important to consider the type of chemical formulation used and any possible antagonism that may occur in single or with multiple product tank mixes," Mr Campbell said.
"With the addition of multiple products and different formulation types to a tank mix, a better quality water is required to be used when compared to single tank mixes."
If farmers get a water test and need more information with what to do based on the results, the Grains Research and Development Corporation website has plenty of sources available to help understand the next steps.