Holmans push effluent uphill

THE management of dairy effluent provides many opportunities for dairy businesses.
The Holman family of Loch has met the challenge of effluent application on a steeper property by expanding their application area by installing a mainline last year.
They are now starting to see the benefits of improved pasture growth.
The Holman property has steep slopes across part of the farm which makes the pumping of effluent challenging.
The dairy operation milks approximately 400 spring calving cows. Manure from the yards is collected into a solids trap and a 50,000 litre sump.
The sump is pumped daily to pasture using an effluent pump via a 1300 metre long mainline and a gun irrigator.
Expanding the effluent application area has enabled better use of the nutrients in the effluent, particularly potassium and nitrogen.
The gun irrigator is moved around every couple of days.
Andrew Holman said, “I’m able to apply nutrients now to areas of the farm that were difficult to drive over and apply fertiliser to, and we’re really able to see a response.”
The effluent was tested and in one megalitre (1,000,000 litres) contained 232kg of potassium, 95kg of phosphorus, 22kg of sulphur and 200kg of nitrogen.
This is equivalent to around 0.46 tonnes of potash and 0.43 tonnes of urea and one tonne of single superphosphate with an approximate value of $1015 per megalitre (prices are a rough guide to illustrate value of effluent).
Each year approximately 7.4 megalitres is generated on the property with a fertiliser equivalence value of around $7511.
Reducing the on-going maintenance cost of the effluent system is also needed to gain the most value from the nutrients in the effluent.
Management challenges for the Holmans’ effluent system include being able to generate enough pressure at the irrigator and managing solids so they do not create blockages in the pipes.
Mr Holman used a plumber to size the mainline to ensure it was the right pressure rating for the steeper property to ensure pumping efficiency and reduce the risk of splitting pipes.
Solid material from the effluent is removed by a trap, but some solid material does enter the sump which gets agitated and applied daily to pasture.
Mr Holman said having the ability to flush the mainline was important to remove solid material if it does get pumped through.
Placing hydrants at 50m intervals for the first 200m of the mainline then 100m after that is something Mr Holman would do differently next time to enable ease of flushing.
He also removed the foot valve on the effluent pump (which is immersed on a pontoon) to allow effluent in the line to drain back to the sump when turned off to flush the pipe.
The mainline has also been buried to protect it from stock trampling, and to help reduce blockages by keeping the pipe cool over summer, reducing the baking of manure inside.
Two posts and horizontal rails have been placed around the hydrants to protect them from stock and machinery. Mr Holman prefers managing the effluent on a daily basis.
“At the end of each milking the effluent is gone; it’s not another job that I have to. There are no excavators, tankers or weeds on dams to deal with later,” he said.
These are the benefits of a direct application system, however it can be difficult to manage these systems when conditions are wetter. It is therefore essential to have some back up storage capacity for these conditions.
The Holmans have back up storage dam where effluent can go if conditions become too wet.
The Melbourne Water Rural Land program has supported the installation of the effluent mainline through a 50 per cent co-contribution financial incentive.
For more information about the program and eligibility, go to: www.melbournewater.com.au and search ‘Rural Land Program’. For more information contact Benita Kelsall, DEDJTR Ellinbank.

Paving the way: Loch farmer Andrew Holman is enjoying the benefits of applying effluent to steep country.

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Posted by Sarah Vella on Dec 1 2015. Filed under Rural News. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry