Altering soil’s structure

Compost - an arable future


On Farm
A lime and compost mix ready for spreading at "Oxenthorpe". At the middle of an eight year program, Stephen Leisk is more than happy with his soil tests, crops and bank balance.

A lime and compost mix ready for spreading at "Oxenthorpe". At the middle of an eight year program, Stephen Leisk is more than happy with his soil tests, crops and bank balance.

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Compost is shifting the balance of one farm.

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STEPHEN Leisk, “Oxenthorpe”, northwest of Molong, is in the middle of an eight year composting program that is literally transforming his land from quite marginal country, to a viable farm.

He laughs as he describes the 162-hectare holding about 650 metres above sea level on east-facing slopes comprised of granite sandy loam hot with aluminium as “the plot no-one wanted”.

It's had 10 owners in 100 years because, as Mr Leisk says, "no-one could make it work".

He bought it 14 years ago and initially couldn't make it work either.

"We tried cattle and it was a disaster, we were running 27 cows, we sacked them and bought ewes.

"With sheep it wasn't much better, we managed 12 days' grazing a year per hectare and were running 100 sheep."

In 10 years of pain he watched thousands of dollars of synthetic fertiliser dissipate into what is essentially sand atop an inhospitable subsoil.

He shows me a gateway and explains the new posts that hold it firm.

“That pole is six metres long, it took three hits of the driver to sink the first three metres, then they just welded another on, same deal again, then left it,” he said. 

Mr Leisk moved from Sydney to “Oxenthorpe” - between Molong and Cudal - with "no idea about farming".

He reckons he was probably better off for the fact he had no idea or he may not have made the trip.

After playing traditional farmer, studying the economics of what he was doing, seeing it didn’t add up and armed with a science degree, he stood convinced there had to be a better way.

Now he reckons he's onto it.

He wants to make his place resistant to drought and resilient in its response to rain and animal grazing. 

A NEW APPROACH

ON THE eve of spring Australian Native Landscapes moved a spreader onto the next 16ha of Mr Leisk’s property to be treated with a "black lime compost" blend – one part lime to four parts compost.

A week earlier Mr Leisk had released 200 lambs for weaning onto 20ha of April-sown oats that were brushing 60 centimetres on a gauge, where ANL first unloaded compost four years ago.

It had a top up of 60 kilograms of DAP/ha at the time of sowing and a total of 35 millimetres of in-crop rain.

“It’s good to see them on some green,” said Mr Leisk, who had been hand feeding them pellets for six weeks.

He pointed out a fairly consistent spread of wooly pod vetch through the oats that has persisted for four years.

Blending the compost with lime eliminates the usual plumes that follow a spreader, said Mr Leisk.

“I don’t like seeing plumes of material I’ve paid for blowing away in the wind,” he said.

“Mixing the lime and compost, the compost seems to act like a magnet, not only does it stop the lime blowing around, but it stabilises it and extends its life,” he said.

“The compost also holds moisture and adds carbon to the soil, and carbon is the driver of everything.”

Repeated sowing of oats is helping prepare the soil for sowing a permanent pasture, reducing the weed seed bank and feeding his Australian White flock.

Permanent pastures would have been planted this year, but premier digit seed is hard to come by and put paid to Mr Leisk’s plans.

ADVISER CONVERT

ANL agronomist Roger Crisp began his association with agriculture on his family’s broadacre cropping farm near Parkes and then moved into managing corporate cropping operations.

But it was an interest in organics and ANL applying it on a large scale in agriculture that caught his eye.

He made the move. One of the first clients he became involved with was Stephen Leisk.

“He was very passionate about looking for a new system to improve his productivity,” said Mr Crisp.

“He’d been using synthetics with limited success and a lot of expense and he knew it wasn’t quite the answer he was looking for.”

Asked how compost stacked up against synthetic fertiliser, Mr Crisp said there are a lot of benefits.

“They offer a complexity of the trace elements and nutrients that we need for maximum growth and good healthy growth of our pastures and our crops.

“Whereas we’ve been steered a lot with synthetic fertiliser into single application nutrients, with nitrogen, phosphorous and potassium being the main ones.

“With a compost you can actually add all those elements plus your trace elements, your zincs, boron and manganese, which are really essential to efficiently use nitrogen and phosphorous, they’re all put into the mix with the compost, so you’re putting them on each time you do an application, which is a lot more sustainable,” said Mr Crisp.

He said the levels of organic matter that compost added was one of its biggest benefits.

SOIL TESTS

Mr Leisk has set about creating baseline data from the first paddock treated four years ago.

He has soil tests from 2013, 2015 and this year and the results are impressive.

The carbon levels in his soil have elevated from marginal to optimum.

Chloride levels that were non-existent in 2013 have well and truly pushed into optimum within four years.

Electrical conductivity, essentially moisture in the ground, has become optimum, whereas in 2013 in was non existent.

There are other elements also, calcium, sodium, magnesium that have have appeared on what was a sparse graph four years ago.

And sulphur is diminishing. For Mr Leisk, the economics of compost versus synthetic fertilisers are appealing.

He can apply the organic stuff for about the same price as synthetics but reaps benefits long after super phosphate or DAP would have had its day.

This means lighter than usual fertiliser applications at sowing allow crops to capitalise on what is already happening in the soil.  

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