This article is sponsored by Rabobank
THE commercial realities of food production are essential to the debate over agricultural sustainability. You can’t be green if you are in the red, so the saying goes.
A southern NSW beef enterprise is showing how recycling urban waste into black organic compost is a good way to get into, well, the black.
In fact, organic compost is not just good for the bottom line.
In an effort to deal with growing rubbish removal and landfill headaches, states are looking to grow markets for recycled urban organic waste, which is sorted by the resident and contains food scraps, green waste, garden clippings and so on.
Governments across the country are at different points in market development, but they are all pushing plans to sort organic material out of rubbish bins and compost it into a commercial product.
Beef consultant Nick Huggins has demonstrated the potential benefits of recycled organic compost on a 400-hectare property perched in NSW’s Southern Tablelands at Mulloon.
In May last year he surface spread a blend supplied by Australian Soil Management across five paddocks at a rate of eight tonnes per hectare over 22ha and a cost of $800/ha. His investment generated an impressive increase in pasture dry matter and carrying capacity.
Mr Huggins reported dry matter gains between 23 per cent to 49pc, as measured in May this year.
“The compost produced moderate to spectacular increases in feed quantity across the paddocks, while feed quality, while very good, was unchanged,” he said.
“The compost got us five years ahead in our grazing plan at Mulloon and now we can focus on animal health and pasture improvements.”
Mr Huggins crunched the numbers on carrying capacity, using the assumption that on average a 450 kilogram steer eats two per cent, or 9kg, of its bodyweight a day.
BY THE NUMBERS
On untreated pasture a steer would need 25 square metres/day if it was grazed to the ground.
If grazed at a more sustainable level of 30pc forage use, it would need 83m2 a day at a stocking rate of 120 head on each hectare/day.
On compost-treated pasture, a steer would need 20m2 a day if the pasture is grazed to the ground, or 67m2 at 30pc forage use it would need 67m2 a day, at a stocking rate of 149 on each hectare a day.
He expected the gains from compost use would be maintained with effective grazing management.
“We aren’t talking about superphosphate. I don’t want to do this every year. I only intend to do it once.
In 2016, after the compost was spread, Mullon enjoyed a wet spring and good growing season, which typically kicks off in November after the ground has warmed up from the chills of winter.
Mr Huggins targeted compost application to paddocks which already had decent amounts of dry matter.
“I worked on the principle of making good paddocks better. The bad paddocks we couldn’t control the variable impacts such as kangaroos, deers and rabbits.”
“I work with everyone from blockies to bigger farmers. Organic compost could find a use anywhere. It just depends what you want to achieve in your operations.”
The paddocks at the Mulloon property had decent ground cover prior to the treatment, which helped the compost break down into the soil and boost soil moisture retention.
“The ground cover helped it bed down and not get washed away in rain. The increased canopy slowed evaporation down and helped circulate moisture beneath the canopy. When it warmed up most plants grew, both annual and perennial.”
Mr Huggins said widespread composted soil could landscape scale benefits.
“We should be slowing water down across the land, but now it just runs across it like a coffee table, and goes straight out to sea.”
WASTE NOT WANT NOT
A new market for farmers to use compost could return a significant portion of urban waste to the soil, to replace nutrients and organic matter that was withdrawn for food production.
Organic compost deployed by beef consultant Nick Huggins at a Mulloon beef enterprise helped soil health and powered pasture production potential.
Each year about 20 million tonnes of organic material is collected and 13mt is wasted in landfill while just 7mt is composted.
When farmers cotton-on to recycled organics, even all the current 20mt collection will not spread far. Virtually all Australia’s 384 million hectares of farmland needs organic matter.
The average Australian farm’s soil contains 3pc or less organic matter in its topsoil, well short of the 5pc healthy benchmark. The shortfall works out at 50 tonnes of compost per 1ha.
But there is expansion potential, given recycled organic composting is yet to hit its straps.
Feed analysis at Mulloon showed minimal difference in feed quality between treated and untreated pasture on the property, with protein fractions, fibres and solubilities “virtually identical”.
“Simple carbohydrates, sugars, starch and fat were also the same,’ Mr Huggins said.
Pasture “wet” weight without compost treatment was 6191kg/ha. Its dry weight was 3634kg/ha (58.7pc). Pasture “wet” weight with compost was 8353kg/ha and its dry weight at 4460kg/ha (53.4pc). Compost improved pasture dry weight by 23pc.
Soil tests showed improvements in all nutrient deficiencies, the marked a four fold increase in available phosphorous.
There was also a 50pc or greater improvement in organic matter and carbon, total nitrogen, nutrient availability, calcium, copper and boron; pH rose 5.52 to 6.07 for 0-10 centimetres and 5.77 to 6.10 for 10 to 30cm.
This article is sponsored by Rabobank