Nutrient reuse grows cheaper grass

Hastings dairy farm has a herd of 350 cows.

With nearly 120 hectares of mainly irrigated dairy pasture and a herd of 350 cows, Hastings Park in the NSW mid-north coast is a highly productive farm.  The cows produce approximately 2.6 million litres of a2 Milk™ annually.

Leo and Sue Cleary, owners of Hastings, were eager to implement a project for distributing dairy waste water over a large part of the farm to assist pasture growth over the whole irrigated part of the farm. 

So, in 2017, when The a2 Milk™ Sustainable Agriculture Landcare Grants program was launched, Leo and Sue applied for a grant.  They were one of four a2 Milk™ farmers who received grants for projects that enhance the sustainability of their operations.

Their project had multiple objectives, including capturing and reusing nutrients from dairy wash-down, reducing dependence on chemical fertilisers with the goal of benefitting a large part of the farm with effluent reuse, and improving the profitability and sustainability of the farming business.

Leo Cleary received an  a2 Milk™ Sustainable Agriculture Landcare grant for a project to enhance the sustainability of operations on his dairy farm.

Two 50-metre long trenches were built with plumbing. This enables washing-down water to flow into the first trench allowing solids to fall to the bottom.  The overflow then repeated the process in the second trench.

Injecting effluent water from the storage dam into the irrigation delivery line at a 10 percent volume was the next stage of the project. The shandied water is then being used to enrich the irrigation reducing the farm’s reliance on chemical fertilisers.

The project has been very successful with these practices now ongoing.  Up to 90 percent of solids were removed from the wash-down water and overflow from the second trench continues via a pipeline to the storage dam.

Very importantly, the Cleary’s now have the ability to distribute dairy water over a large part of the farm which assists pasture growth over the entire irrigated part of the farm by 90 percent. 

Further, the water required for irrigation has been reduced by 10 percent by substation of that percentage of dairy waste water.

Leo also reports that observation of pasture density and growth rates has shown acceleration in both regards over time after effluent reuse. This has allowed less nitrogen fertiliser to be used.

The next step in the project will be for solids to be collected and dried, then spread on 40ha of land prior to the summer crop of sorghum being planted in October 2019.  This spreading of solids from the trenches is further reducing fertiliser needs benefiting the farming business by reducing costs and improving the soil quality.

Leo commented that “With this project we’ve learned that mixing dairy effluent water with irrigation water is an effective method of using dairy waste and that capturing solid waste for later use in a trench system removes a high percentage of solids.”

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