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      Microbial culture revives “dead” pond
Yurunga Farms co-principal, Adam Marshall, and Semex Area Representative, Howard Hodgetts, in front of the effluent pond six weeks after treatment with BioAg Digest-it® for Dairies. The dark patches show where the thick, dry crust is starting to break up due to increased microbial activity. The use of a new “biologically active” microbial culture has brought an otherwise “dead” effluent pond back to life on a Riverina dairy farm. Lachlan and Genevieve Marshall, together with Lachlan’s brother, Adam, milk 550 Holstein cows that produce almost five million litres of milk a year at Blighty, NSW. According to Lachlan, the effluent pond on “Gunyah Park” was all but dead when the brothers purchased the property three years ago. “It wasn’t working at all,” he said. “It was full of solids, crusted over and the liquid was overflowing into the recycle channel. “We completely emptied it and cleaned out all the solids, which we spread over 45 hectares of paddocks as fertiliser. “We let the pond refill but it remained dead because there were no bacteria in it. “It took more than a week and cost us $5000 to clean it out and spread the manure but before long it was just as bad as before.” Last spring, the Marshalls agreed to participate in a trial using BioAg Digest-it® for Dairies, a fermented culture that helps to create and maintain a balanced microbial environment in effluent ponds. Developed by Narrandera company, BioAg, it provides a rich source of dormant aerobic bacteria and an additional food source for microbes, thereby stimulating microbial digestion of organic matter. Depending on the thickness of the surface crust, a number of physical and chemical changes can be observed in ponds within four to six weeks of treatment. These include increased bubbling due to increased aerobic microbial activity and reduced surface crusting, turbidity, solids and odour. In the longer term, nutrients that are otherwise “locked up” in suspended solids are converted into a rich source of plant-available nutrients, which can be applied to pastures. This reduction in solids also reduces the need for desludging. “We’d heard good things about the use of Digest-it® as a stubble treatment so we had no problems about taking part in the trial,” Lachlan said. “We really had nothing to lose – it was either give it a go or pay another five grand to get the pond vacuumed out again.” The Marshalls “kick started” microbial activity by adding 40 litres of Digest-it® to their pond in mid-September. Since then, they have poured two litres of the product onto the concrete apron before it is hosed down after each morning’s milking. Adam said the pond had been brought back to life and the dry surface crust was gradually being replaced by an active, bubbling liquid. “Digest-it has definitely done the job,” he said. “The microbes started working within hours and now you can see them at work along the full length of the pond, bubbling and foaming. “It’s taken a bit of time to get the microbes back up to a functional level but it’s starting to really kick into gear now. “We’ve seen a gradual breakdown of the solid crust in areas where it was thick and there’s been a vast improvement in the smell of the pond – in fact you can’t smell it at all. “The overflow water, which goes into a recycle channel and into our irrigation system, is still green but it’s not as dark as it used to be. “I’d say the pond is 75 per cent of the way there, which is pretty good considering that our microbial levels were almost zero after we’d vacuumed it out.” Adam expects that the improved microbial activity in the pond will significantly reduce the need for desludging. “We hoping that we won’t have to clean the pond out for another five years instead of three,” he said. “And when it comes time to clean it out, the solids in the pond will be more completely broken down and will put lots of available nutrients and beneficial microbes into the soil.” The Marshalls intend to continue to using BioAg Digest-it® for Dairies in the effluent pond and also to treat their corn and sorghum crop stubble to convert residues into available nutrients. “We don’t have a lot of topsoil around here for microbes to live in so the easier we can make the job for the plants, the better,” he said. BioAg Digest-it® for Dairies is distributed by leading livestock genetics organisation, Semex Pty Ltd, which employs six full-time sales representatives throughout Australia. |
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