Facing rising input costs and greater environmental awareness, an increasing number of Australian vegetable growers are practicing a system of farming that has come to be known as ‘regenerative agriculture’.

Regenerative agriculture means different things to different people, but in a broad-brush sense it’s a holistic way of managing landscapes that aims to move beyond sustainability to regenerate natural systems, while at the same time supporting the viability of farmers.

On farm, that generally translates to practices that improve soil health, store carbon and increase biodiversity, which, importantly, improve yields and reduce input and water requirements.

There isn’t a clear definition of which is and isn’t regenerative agriculture, but it’s commonly understood to involve practices like cover cropping, minimal tillage, rotational grazing and biological inputs, among others. It’s a broad church, and the exact practices used by adherents vary depending on their crops, soil, climate and how far along growers are in their regenerative agriculture journey.

The best way to understand it is through five core principles, according to Andrew Johanson, the Sustainable Agriculture Manager at Mulgowie Farming Company, a family owned vegetable grower with five farms in Queensland, New South Wales, and Victoria.

“There’s no ‘hard and fast’ like organics where you must follow certain rules,” he explains. “There are five core principles, and they are minimise soil disturbance, maximise crop diversity, keep the soil covered, maintain living roots year-round, and integration of livestock.”

Mulgowie has been steadily moving towards what is now called regenerative agriculture for a long time. The business adopted integrated pest management in the 1990s and controlled traffic in the early 2000s. In more recent years, Mulgowie has begun using compost and closely monitored application of foliar fertilisers.

Levy-funded research has helped the grower in its regenerative agriculture journey. Mulgowie has run several trials at their farms through the Soil Wealth ICP project, investigating topics such as strip tillage and soil biology.

“It’s been fantastic being part of the Soil Wealth project,” says Andrew. “We’ve had Stephanie Tabone and Dr Kelvin Montague very involved with a few projects on our farms over the last five years. They’ve been very helpful; if we’ve got a question or want to fix an issue, we can go and ask them and trial it and see what we can work out.”

One of Mulgowie’s regenerative agriculture-managed bean crops

The regen ag cycle

The regenerative agriculture process, as Mulgowie Farming Company practices it, starts at the point of harvest.

At the point of harvest, Mulgowie assesses the paddock, and depending on the state of the soil, and whether it was a wet or dry harvest, determines if the soil needs to be worked up or can be mulched and planted into directly.

“We take a shovel or a penetrometer and feel the soil and make decisions based on that,” says Andrew. “We want to get compost onto the ground and compost normally needs incorporation, so there’s a fine line of knowing when you’re going to need to have your ground ready for reforming.”

Mulgowie usually applies compost once or twice a year in the off season. A biochar and manure mix is spread on the paddock and then incorporated, sometimes by animals
through heavy livestock grazing for one to two weeks.

That’s following by hilling up the soil and redraining the paddock, after which the ground hopefully doesn’t need to be reworked for the rest of the season. Ground disturbance disrupts soil biology, and reduces organic matter and water infiltration, and minimising it is an important component of regenerative agriculture, according to Andrew.

Groundwork is also expensive and time consuming, and Andrew says the first three years of following a low-till approach in Mulgowie’s Bowen farm resulted in a 43 percent reduction in fuel consumption.

Planning a cover crop is the next step after manure incorporation. Keeping the soil covered and having living roots in the soil as much as possible are principal tenets of regenerative agriculture, so if a cash crop is not going to be planted straight away, Mulgowie will sow a cover crop.

“Some cover crops are extremely quick; a crop like buckwheat, for instance,” says Andrew. “We grew a massive amount of organic matter in 25 days with buckwheat – it was nearly waist height in 25 days in November in the Lockyer. It’s a really good cover and very good for the soil as well.”

The cover crop is then terminated and mulched, and then the next crop can be planted directly into the stubble.

That’s difficult with fine seeded crops like carrots, but for large seeds or transplants like Mulgowie’s corn, bean and broccoli crops it’s manageable with the right planting gear, such as trash throwers and coulters.

Following the harvest of that crop, the cycle begins again.

The right nutrients at the right time

Mulgowie creates their own compost using biochar, manure and recycled plasterboard

Regenerative agriculture has helped Mulgowie to significantly reduce its use of synthetic fertiliser. The grower has taken something of a two-pronged approach, increasing the level of bioavailable nutrients in the soil with biological inputs, and a scientific approach to the application of nutrients to make sure only the right nutrients are applied at the right time.

“We’re trying to reduce synthetic fertilisers as much as possible, and especially nitrates,” says Andrew. “If you can get plant-available nutrients naturally rather than applying chemical fertilisers, your crops’ quality and yield is just so much better.”

Mulgowie’s compost mix varies across their farms depending on what is available locally. It’s primarily compost based, either cow manure or chook manure mixed with straw bedding from a chicken farm. Mulgowie actually supplies the straw bedding themselves.

“We grow wheat in the winter and sell the straw to one of our manure suppliers, then we buy that back in with the manure,” says Andrew. “It’s another good cyclic story.”

The manure is mixed with biochar, at a rate of around 70kg per hectare, as well as an unusual ingredient – recycled plasterboard – before being composted.

“It’s rejected Gyprock plasterboard directly from the factory, which is available locally here,” explains Andrew. “It’s the purest calcium sulphate mined in South Australia, put between two bits of paper. When it’s composted properly with the manure, the paper breaks down and you’re getting your calcium sulphate cheaper and not having an extra spreading cost.” Manures from feed lots or chicken sheds are reliable as they are on a consistent diet, which helps knowing what nutrients you’re getting. Consistent, clean compost ingredients is important.

While the regular application of compost builds the base of nutrition in the soil, Mulgowie also applies foliar fertilisers at very specific times, with the results in the crop monitored by sap testing.

Mulgowie has adopted the ‘Critical Points of Influence’ system developed by US agronomist John Kempf.

“It’s all about how every plant has its critical stages where you can influence yield and get it to its best genetic yield potential, making sure they’ve got the right amount of the right nutrients at those stages with foliars,” says Andrew.

Mulgowie has followed the system for the past two years across three different growing regions, and have seen outstanding results. Product weight, nutrient density, and shelf life has improved, while synthetic fertiliser use has dropped 40 percent.

One of the grower’s most important discoveries has been the benefits of reducing nitrogen.

“We tend to overuse nitrogen in agriculture,” says Andrew. “You make plants grow very quickly, but you end up with weak, watery cells that break down quickly. Nitrates block a lot of your other nutrients, and to build a strong, healthy cell you have to ensure it’s got enough calcium, silicon, boron and everything else.

“People look at you strangely when you say we’re actually aiming to have zero nitrate in the sap of our plant. It doesn’t mean we’re growing the plant without nitrogen, ultimately the goal is to have soils with abundant microbiology supplying abundant nitrogen in the form of amino acids to the plant.”

Reducing nitrate levels in the crop makes the plant less attractive to insects and not as open to disease, Andrew explains.

“We’ve seen the reduction in insect pressure and disease pressure and the increase in quality with building those cells and shelf life,” he says. “We’ve measured the amount of nitrate in our end product and it’s extremely low. That’s the aim.”

A case study on a Soil Wealth ICP legume cover crop trial on one of Mulgowie Farm Company’s properties appeared in Australian Grower’s Summer 2024/25 edition.