A joint project between Victoria's Department of Primary Industries and the Geoffrey Gardiner Foundation has found a way to re-use dairy sludge.

While visiting John and Dianne Kuriger's Naringal farm trial site last week, Victorian Agriculture Minister Joe Helper said that in the past the semi-solid sediment which forms on the bottom of dairy farm effluent treatment ponds, has been regarded by farmers as an "undesirable and inconvenient waste by-product".

"Although it has been recognised that dairy sludge has a high nutrient value globally, this is the first project to demonstrate its successful use as an alternative nutrient source for Victorian soils," Mr Helper said.

"Results from the first year of trials suggest the nutrients in dairy sludge are very effective for promoting growth of both established pastures and forage crops.

"Although the nutrient content of each pond varies with the proportion of water content, typically dairy effluent contains nitrogen, phosphorus, potassium and calcium – the range of nutrients commonly required to maintain soil health on Victorian farms."

During the DPI trials the sludge has been applied at different rates on pasture and forage crops at two sites in the south-west: the Kuriger's Naringal farm and at Terang's Demo Dairy.

"Production responses are being measured by scientists to determine the value of sludge as a fertiliser," Mr Helper said.

"The timing and length of these responses, the effect on herbage quality and mineral content and the effect on soil fertility and health are also being measured."

The project's preliminary results are exciting and have the promise to change the way dairy sludge is viewed by the industry.

Substantial increases in pasture yield have been recorded throughout the entire growing season, including winter.

Even in cold and wet conditions there is still active mineralisation of the nutrients from organic to plant available forms.

This is quite different from studies in the northern hemisphere where winter responses to sludge are very low and ineffective.