Waste can be a bonus if treated well
There is no escaping the fact that in producing 650,000kg of milksolids annually, 1600 dairy cows will also emit an equally massive volume of waste!
However, says Waverley dairy farmer, Will Dickie, when you have the right systems in place to cope with this, that waste, in the form of effluent, becomes a bonus instead of a problem!
The property owned and operated by the Dickie family switched from dry stock farming to dairying nine years ago.
‘‘My grandfather would have said that this is unproductive land and certainly not dairying country,’’ he says.
‘‘It’s mostly sand country, and from 1971 until 1987, sand was mined from the neighbouring property. Over those years, 15.7 million tonnes of concentrate was extracted.
‘‘Our 1600 cows have been divided into four herds, and are farmed on two adjoining properties. Both milking platforms comprise 250 hectares of grass and near identical effluent irrigation systems have been set up on each.
The first of these was installed nine years ago, and the second, five years ago.
‘‘Over time, the system we have set up to spray effluent on to our pastures has developed into an amazing resource – in fact the best that we have, in that over time it transforms unproductive land into productive farm land.’’
The most recent effluent irrigation system was installed five years ago and cost approximately
$135,000 to set up, says Dickie. The cost included a high specification flood-wash ($30,000); weeping wall filter system
($50,000); pond ($40,000) and pump
($10,000-$15,000).
‘‘Both systems would have paid for themselves within three or four years. We went for a bit of a Rolls Royce version of effluent irrigation with the system installed five years ago, and I guess that if we had bought a more basic version, the breakeven figure would have been reached even more quickly.’’
With both systems, all of the effluent from the yards is captured by a flood-wash and fed through a weeping wall, which separates the liquid from the sludge.
The liquid then goes into holding ponds, which with the newer installation, has approximately
150 days of storage.
The effluent from which the solids have been separated is either pumped back up into the green-wash tanks and used to clean the yards of the farm dairy, or on fine days, when the weather permits, is pumped out from travelling irrigators on to the farms.
There are two major benefits from the effluent irrigation programme, says Dickie.
‘‘Firstly, we get a contractor in to spread the solids, which over time, will build up organic matter and secondly, through using the spray irrigators, we can keep the grass in a green and vegetative state over summer.
‘‘Whereas the grass would normally dry out, through using the spray irrigators, we can keep the grass green and keep the nutrients going on to it, which means that when the rain comes, we are a step ahead.
‘‘The effluent irrigation systems have the capacity to spread the effluent over 120 hectares.
‘‘The nine-year-old system is identical to the most recent installation and is sprayed on to slightly stronger country, but which still has a sand base.’’
Through making strategic use of spray irrigation on sandy soils, tens of thousands of dollars are saved in fertiliser costs, claims Dickie.
‘‘We soil test every paddock on the whole farm,’’ he says.
‘‘We know paddock by paddock what the nutrient requirements are and we get our fertiliser company to draw up a fertiliser application plan.’’
Apart from a requirement to manually shift the travelling irrigators from paddock to paddock, the effluent irrigation process is completely automatic.
‘‘There is remote monitoring and everything is done by the press of a button,’’ says Dickie.
‘‘We recently installed a system which can be monitored on a cellphone. There are alerts too if the pressure drops, or the pump turns off sooner than expected.’’