IT’S really all about maths.
Neridup farmer John Wallace fondly remembers 2007 as the year when crop prices spiked while fertiliser prices remained relatively flat.
There was plenty of puff in continuous cropping – despite the exponential growth of herbicide resistance throughout the Wheatbelt – with a focus on improving crop productivity through technology advances and new crop varieties.
A decade on and farmers are more circumspect about the best way to make the proverbial quid on the farm.
For Mr Wallace it has to be about diversity.
“In 2007 we were getting $400 a tonne for feed barley and we were growing four tonnes a hectare,” Mr Wallce said.
“Today you’d be lucky to get $200 a tonne.
“Compare that with running sheep where you could conservatively be banking $350 a hectare.”
It’s a truism that the majority of farmers who have remained successful over the past decades, never went out of sheep or cattle.
And Mr Wallace believes there is somewhat of a paradigm shift occurring in WA agriculture skewed towards a mixed farming regime.
“I think it’s fairly obvious that for at least the past 20 years, there has been a huge loss of organic nitrogen from the soil from continuous cropping, which has been driven by revenue, which is not there now,’’ he said.
“Then you’ve got herbicide resistance issues, which apart from weather damage, underlines the risks associated with sticking to a monoculture system.
“I vividly remember 1980 when frost almost knocked us out of the game.
“That taught us a big lesson to mitigate risk, which is why we never got out of stock.”
Today Mr Wallace oversees an 80:20 crop:sheep enterprise, using 20 per cent of his land for high winter grazing because it is not suitable for mainstream cropping.
He carries 5000 ewes and generally sits on 12 DSE in grazing paddocks.
Serradellas, biserrulas, medics and saltbush can all contribute to increasing yields while at the same time filling summer and autumn feed gaps, building up soil structure and organic nitrogen levels and providing a measure of weed suppression.
In late October, Mr Wallace established his first long-season CL970 canola crop as part of his grain-graze management of his stock.
“We could get up to four grazings from the canola which would be about 6t/ha equivalent of food for the sheep before we lock the crop away in June,” he said.
He also has a long-season feed barley variety called Yarumbi, which he establishes in late February or March for one or two grazings to eliminate the autumn feed gap, before locking it away as a crop.
The focus is to improve soil structure and soil health.
“About 40pc of our soil is good loam, 50pc is transitional mallee (sand-over-gravel-clay) and 10pc is sand,” Mr Wallace said.
“So we’ve been claying, using the DBS to get plant roots down into the soil and generally taking a systems approach to the way we farm.
“Our annual rainfall is between 450 and 550 millimetres with 25pc of that over summer, which is a bonus for our system because we can sow crops such as vetch, which is deep rooted, provides good biomass and also fixed nitrogen.”
Organic N also is emphasised with Mr Wallace’s selection of plant legumes to complement long-season canola and barley varieties in a grain-graze regime.
He is also keeping an eye on emerging varieties such as the salt-tolerant Neptune messina annual pasture legume and Anemeka saltbush.
The Neptune messina has a higher combined tolerance to salinity and water-logging than all other current pasture legumes.
The Anemeka saltbush, has better palatability and digestibility than oldman saltbush and also has good biomass for feed and as a competition to weeds.
Murdoch University is involved in a $16.6 million Federal government-funded five-year project to boost profit and reduce risk of mixed farms in low and medium rainfall areas.
The university’s contribution is promoting new grain legume varieties along with identifying the correct rhizobia for selected varieties – mainly WA-bred and South African rangeland species.
University project leader John Howieson said the national project represented a shift in mixed farming management.
“The sheer bulk of material from these varieties is enough to feed stock, provide competition against weeds and fix nitrogen,” professor Howieson said.
“That means less cost on supplementary feeding during dry spells and fewer sprays to control weed burdens.
“And with fewer sprays, you’re negating, to a large extent, resistance pressures.
“Plus there’s the benefit in soil fertility which is ongoing.
“We’ll probably always be facing a moisture-limited scenario but the big point with, why we might call pasture-ley, is there’s less risk and less cost in growing crops, even in years when frost knocks the bottom line, because you haven’t spent money on nitrogen to the extent you normally would.
“We know costs are a major adoption barrier and this project will focus on inexpensive options.
“Establishing legume pastures are likely to be less than $100/ha, and in many cases can be amortised over 20 years, because these legumes regenerate on demand.”
Regenerate on demand is a term researchers coined that implies the farmer chooses when to keep the regenerating pasture for feed and N production.
It could be the year after crop, or the second or third year – depending on what the farmer “demands” in any given year.
For Mr Wallace, using “natural” ways to improve soil fertility is key.
“I go back to the systems approach,” he said.
“You get the right tools to do the job and give Mother Nature a helping hand and generally she looks after you.
“If you can increase soil fertility, it provides better feed for the stock and healthier-yielding crops.”