THE MONO and duo cultural crop rotations made possible due to synthetic fertilisers and cheap herbicides and popular through many parts of Australia may have just about run their race - but the industry will be able to adapt successfully.
This is the opinion of Tim Reeves, the professor in residence at Melbourne University's agriculture-focused Dookie Campus.
"The balancing act is getting sustainable intensification," Professor Reeves told the Victorian Farmers Federation (VFF) grains conference in Moama last week.
"You obviously want to improve profitability but also take your eco-system health with it as well," Prof Reeves said.
"The take-home message is that we are going to need to get more efficient, the world may need double the food by 2060 but it ain't going to be grown with double the water - we just don't have it.
"Water use efficiency is going to be critical, while reducing reliance on fertiliser and herbicides will also be important."
Prof Reeves said Australia had been a leader in the conservation agriculture movement over the past 30 years but added the current heavy reliance on limited crop rotations and chemical solutions to weed management were not sustainable.
However, he was confident it was something the industry would work through.
"We went through all this in the 1980s, getting farmers to grow lupins and canola and things they had never heard of, so while we think changing up the system is difficult we have been there before and can do it again."
Prof Reeves heaped praise on the conservation ag movement in Australia, but said the missing piece of the puzzle was diversification.
"Conservation ag has been extremely good for cropping in Australia, but the bit we are missing is that diversification, just a wheat-canola rotation is not sustainable."
He urged farmers to not only think of more diverse crop rotations but to also consider options such as pastures and livestock and even other factors like trees and shrubs and developing on-farm spatial diversity.
"We need to think outside the box."
Prof Reeves said plant-based nitrogen (N) would play a big role in maintaining sustainability into the future.
He said there had been a massive shift towards the use of synthetic N that needed to be halted.
"We can't wean ourselves off synthetic nitrogen but we can think how else we can put that N back into the soil and things like pasture legumes do a great job with that."
"There is also the advantage in terms of helping building up soil carbon especially when you include things like deep rooted perennial species."
Prof Reeves said while building soil carbon was a slow process there were other benefits to soil health farmers would see more quickly when they made more sustainable choices.
He told farmers in attendance at the meeting that they would have to plan for big changes.
"It is not something we're faced with yet but the industry as a whole needs to look at how a post-glyphosate environment looks."
While acknowledging it would be a massive change, Prof Reeves highlighted several nascent technologies such as microwave heating to kill weeds as options that showed potential at a research level.
"Whatever you are talking about, business as usual is not going to be a viable option."
"Sustainability is going to be a moving target but it is something we can do."
