Tasmanian Biofumigation pioneers push potato rotations

Biofumigation is being used in Tasmania to reduce vegetable cropping rotations and boost yields.

Biofumigation is a system in which plant chemicals are used to fight soil-born diseases.

USA farmer and biofumigation pioneer, Dale Geis has been sharing his experience in developing brassica varieties with high levels of natural chemical agents, the glucosinolates, that promote soil health and knock off diseases when they're sown, grown and ploughed in as a green manure to the soil.

In Tasmania, vegetable grower and owner of the Sheffield-based MG Produce company, Darren Long, is using biofumigant crops to push the boundaries with shorter cropping rotations.

Darren Long says biofumigant plants should be approached like a commercial crop, with a long-term return, not just a 'charity' crop.

"We do a lot of fresh-market potatoes to the supermarkets and we also do a lot of seed potatoes to the mainland;a fairly big operation,"Darren said.

"We were finding the same as Dale;a lot of disease pressures in potatoes, and we were growing a lot of carrots and swedes and parsnips over the years, and we basically found that we were running higher inputs, and we needed a better green manure.

"It's a whole farm management plan that we've got going, and at the top of the list now is the biofumigation.

"We're at the stage now where we've backed a seven year rotation of potatoes back to five, back to four, and we're just pushing the boundaries now with three [years].

"Rhizoctonia, powdery scab and common scab are the three biggest diseases we've had trouble with and, with the varieties we've got, we've certainly got better soil health on the farm.

"I would say we're certainly getting to control levels where we can comfortably farm on a three year rotation with potatoes.

"Coles and Woollies they've got a high pressure of quality, so if we're pushing good quality potatoes into there, then we know we're going O.K."