Where is the next crop yield jump going to come from now that so many Australian grain growers have adopted minimum-tillage farming and controlled-traffic systems to conserve their soils and store maximum moisture?
That is the tough question central New South Wales grain grower Paul Adam has been contemplating for the past decade on his 2000 hectares of dry farmland near Tottenham, 180 kilometres west of Dubbo, where he grows bread wheat, durum wheat and canola in a continuous cropping rotation in a low-rainfall zone of about 450 millimetres a year.
As a younger farmer, Paul, now 45, put all his effort into slashing input expenditure – especially fuel bills – and improving profit margins per hectare.
He has always been a fierce advocate of no-till farming, halving his costs and doubling his crop yields, even with the added chemical weed control outlays.
System adjustments
A decade later, Paul has adjusted his farming systems once again.
While he remains a dedicated minimum-tillage grower, to both maintain sustainability and preserve as much moisture as possible in his soils, he is no longer so rigid as to never allow a set of tynes, a plough or a cultivator near his paddock stubble.
Simply, Paul says that as he grew older – and after spending six months overseas on a Nuffield Scholarship looking at minimum-tillage cropping systems around the world – he began to question whether a cutting-all-costs approach, rather than a controlling-costs mindset, was the best approach for his farm productivity.
“I found I was sacrificing yield potential in the better years by focusing so much on no-till and low costs across the farm to cope with the bad drought years – and we have had a few. I was too conservative, frankly,” he says.
“Now my focus is on retaining as much soil moisture as possible while also being sustainable, but making sure I also maximise the yield potential of my crops in all years, not just the bad or average ones.”
For Paul, this has meant being flexible enough to make small changes in how he farms depending on each season, chasing the one and two per cent yield gains made from multiple minor steps that together add up to him achieving some of the best yield results for his crops in the region.
It’s all about enabling the soils to store maximum moisture so the crops can perform to their genetic yield potential.
He now uses much more nitrogen fertiliser on the farm ahead of a new crop and when soil moisture is good.
After the heavy spring rains and floods central NSW experienced in November lead to a very delayed harvest – but exceptional yields of four tonnes per hectare for his wheat crop – Paul is lightly reworking some of the paddocks to level them again.
Much of the farm has also been deep-ripped (once only) since 2018, to break apart hard subsoil plough pans from decades past, allowing the deeper soil profile to crack open and boosting soil moisture holding capacity even further.
“It’s all about enabling the soils to store maximum moisture so the crops can perform to their genetic yield potential,” he says.
“Retaining stubble, controlling weeds and minimum tillage remains a huge part of that priority in my business, but I’ve also realised that sometimes you have to outlay on fertiliser and other inputs to make sure that the yields you could achieve from that greater stored moisture aren’t being capped in the best years.”