After 30 years of growing vegetables in southern Queensland, Rob Hinrichsen is well- placed to assess the impact of soil health on his farming operation. Rob founded vegetable production and packing company, Kalfresh, with his father in the Fassifern Valley. The operation has expanded considerably over the years to supply produce year-round.
The passion Rob Hinrichsen brings for growing healthy, tasty, nutrient-rich food centres around healthy soil. Kalfresh is well known for growing carrots, but also produces onions, green beans, sweet corn, baby capsicums and pumpkins.
Crucially, whenever there is a gap in the crop rotation of greater than two months, the operation will put in a cover crop rather than leaving the ground bare.
“With our summer-dominant rainfall, cover crops provide ground protection during the wet season. It’s then much better for our soil – if we do get any form of runoff – to stop the siltation and removal of nutrients from the farm,” Rob explains.
“Also, during the heat of summer, we’re actually capturing that sunlight and turning it into carbohydrate and pushing it into the soil, which is a far better outcome.”
Cover crops are mostly simply direct-drilled into beds when the beans and sweetcorn have been harvested, making the most of residual moisture.
Innovation at work
Controlled traffic farming is also a focus for Kalfresh, and Rob believes it is making a big difference. However, it hasn’t been easy, as the operation originally needed to adapt the technology from industries such as cotton to fit horticultural systems.
“We’re in a very rich, nutritious clay-based soil and driving on it with large machines just destroys it. As soon as we could get our machinery off where we’re going to grow our crops and put it on dedicated lanes, the soil just responded almost immediately,” he says.
“We started making a compost out of used mushroom substrate, which is very high in all kinds of minerals that we need on the farm, and we also used chicken manure,” Rob says.
Another big focus for Kalfresh has been to reduce the waste that comes out of its packing sheds. Some of it can be fed to cattle, while some – such as waste onions – is used to make a more long-term humic-style compost.
Sustainability focus
It has been an evolving journey. The original aim was to grow as many tonnes of cover crop as possible, before shifting to promoting on-farm diversity with multi-species cover crops as a way of maximising soil carbon and reducing pest pressure.
“It’s actually the carbon that the cover crop captures out of the air – and exudes from its roots as a component of the carbohydrate it uses to attract different fungi and bacteria – that is actually bringing our carbon level up, more so than ploughing in tonnes and tonnes of biomass,” Rob says.
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