Mixed farmers Ian and Fiona Koch, Bunyara, Moculta, first started dabbling in polycultures about a decade ago, but are tweaking their program each year in the hope of continual soil improvement, and the results are speaking for themselves.
The Koches run 1800 hectares of owned and leased land, including 400ha for cash and feed crops - comprising oats, barley, wheat, beans, lupins, peas and canola - and 200ha sown for multispecies sheep feed mixes.
The remaining 1200ha is pasture, used for running 1600 Poll Merino ewes split into an 800-head self-replacing flock, 550-head Bunyara stud flock, and 250 head joined to White Suffolks for prime lamb production.
The multispecies sheep feed is sown as a mix and reapt as a mix, containing forage oats and barley, wheat, annual ryegrass, peas, beans, lupins, vetch, and cereal rye.
"In nature, you don't keep one thing growing in one spot, you have 10 different things growing and the ground is covered," Mr Koch said.
"We're trying to keep things natural for the sake of soil longevity - soil health and improvement is our paramount goal."
"This year is the biggest mix we've had - we've been playing around with mixes since 2015. What's in the mix depends on what we can get our hands on. We've put a fair bit of effort into getting more of a mix and expanding it a bit more, prior to that we were just using whatever was leftover and lying around."
Regenerative agriculture is going to become more of a priority with the challenges facing the planet, and growing different crops together is going to be part of this change.
- FIONA KOCH
The Koches' crop rotation involves a wheat crop, then barley or oats, then a break crop of the multispecies sheep feed mix, then a break crop of beans or lupins, or peas and canola.
While the cash and feed crops have traditionally been sown as monocultures for the sake of efficiency, peas and canola are being sown together this year, after first trying it in 2020.
"Peas and canola have different plant architectures and root structures. They work together really well and are a good blanket to smother weeds and competition out," he said.
"Also, we want to retain as much stubble as possible, and when sown together, pea stubble doesn't blow up and all over the fences, and then when we're harvesting, the canola helps peas stand up off the ground to feed into the harvester better."
Mrs Koch said growing polycultures meant a small cost in seed cleaning time and expenses, but the system was still manageable.
"Canola is so small it goes out with the pea screenings, so sometimes there is double handling to then clean canola again, but we have made the time to do that in our farming system," she said.
"Regenerative agriculture is going to become more of a priority with the challenges facing the planet, and growing different crops together is going to be part of this change."
FERTILISER REGIME MODIFIED TO AID SOIL LONGEVITY
IAN and Fiona Koch's fertiliser regime is different to that of many other croppers, in the way that urea is no longer part of the program.
"We have been moving away from chemical fertiliser for about five years, and we're trying to avoid insecticides and fungicides too," Mr Koch said.
Six weeks prior to seeding, a slow-release restorer blend is spread, then a BioBlend and 20 per cent Pro S10 Peats fertiliser at seeding, then a liquid nitrogen fertiliser containing trace elements about two months later, applied with a broadleaf or wild oats spray.
Locally-sourced composted grape marc has also been spread for the past five years, on a different paddock each year ranging in size from 30 hectares to 50ha, spreading at 8-10t/ha.
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"It's mainly a cost thing as to why we don't spread it on every paddock every year - some crops like it more than others, but it helps to reduce soil acidity and increase soil organic matter," Mr Koch said.
"You do obviously get grape seeds in it that last a bit longer, but the vines disappear, and just make the soil softer."
Mr Koch said on-farm soil biology tests showed grape marc had improved soil biology, while yields in the past few years had also been encouraging.
"We had a four-tonne bean crop for the first time ever last year, and we also got some 4t wheat, which is our best wheat crop in years - our changing system is kicking in."
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