Spreading effluent on dairy farms is set to become a lot more high-tech thanks to smartphone-based technology now available for New Zealand farmers.

The new Dairy Effluent Spreading Calculator app can be used to calculate nutrient application rates based on the depth and type of effluent being applied.

It was developed by industry group DairyNZ in conjunction with Auckland's Sales App Centre.

DairyNZ marketing manager Andrew Fraser said the technology allowed effluent to be spread with greater efficiency and precision.


The app's main objective was to save farmers money, rather than provide environmental benefits, he said.

"Potassium, for example, is one of the nutrients that's in effluent so if you aren't spreading it thinly and widely then you end up having to buy more potassium from your fertiliser supplier than you actually need."

Fraser said many farms now had limits on how much nitrogen could be applied to paddocks and the app could help farmers stay within their limits.

The app, available for Android-powered smartphones and Apple iPhones, comes with two calculators - one for spray irrigation systems such as irrigators and sprinklers and another for slurry tankers and muck spreaders. The calculator also determines the area required for spreading.

Theresa Wilson, DairyNZ's sustain-ability team leader, said a survey conducted by DairyNZ in April indicated around 44 per cent of dairy farmers had smartphones, up from just 25 per cent 12 months earlier.

The app can be downloaded free from the Apple App Store and Google Play store.