POTATO grower Darren Long has stripped it all back.
Faced with a Tasmanian vegetable industry saturated with high-input varieties loaded with fertiliser and herbicides, Mr Long has gone back to basics with great effect.
MG Farm Produce, which has provided fresh market brushed potatoes to supermarket giant Coles for the past 17 years, have used a brassica crop as a biofumigant on a commercial scale for the past five years to improve soil health and increase potato yields.
Mr Long said the brassica crop – planted for a 12-14 week stint before and after a potato crop – contains high-levels of glucosinolate, which is a naturally-forming fungicide that helps regenerate soil after harvest.
Once fully grown, the brassica crop is cut, which releases the glucosinolate, and mulched into the soil.
Using the crop has almost halved the potato rotations on the Sheffield farm, helping MG Farm Produce almost double its levels of production.
"Fresh market potatoes are generally harvested once every five years, some of the Russet Burbank varieties once every seven, but we harvest once every three, which is unheard of," he said.
"Biofumigation has saved what we do. Because we haven't got the broad range of crops to grow we had to find a better way of growing potatoes in a quick rotation."
Despite being a profitable idea, planting brassicas is a long-term project, which Mr Long said would be difficult for struggling vegetable producers in the State.
Mr Long said with vegetable prices on the decline, growers were pushing their ground through a variety of different crops to chase the highest price on offer by the processors.
"It (brassica) becomes a charity crop, people think they can't graze it because the glucosinolate is too bitter and cows and sheep won't eat it," he said.
He said growers were reluctant to spell their ground in order to plant the brassica.
"People always want to plant something they can get money off, and this stuff doesn't. They're happy to go and buy a drum of Nemacur and Roundup type products and kill something, but this (brassica planting) is long-term thinking.
The problem with potato growers across the State, according to Mr Long, was they are broad-spectrum farmers.
"Once the potatoes are out the onions are in and then the carrots are in and the soil structure just deteriorates so badly," he said.
"People running high-input crops are running into trouble because they're not getting the returns, they're spending more and more time putting chemicals on to control diseases."
MG Farm Produce have been using a brassica crop imported from the US called Calienta, which has the highest-tested glucosinolate release rates, according to Mr Long.
Calienta, which has been commercially available to Mr Long for 18 months, has been mixed up with a few varieties on the 120-hectare farm to avoid people "pinching it and producing seed themselves".
"Because it germinates well, the breeder (of Calienta) was concerned that if he had this great product people would try and steal it," he said.
A new strain of Calienta – Rocket – has been used in the US for a number of years, Mr Long said, which he hopes to have available in February 2014.
Rocket includes a new brassica variety called Nemat, which is a broad-spectrum biofumigant that will reduce the nematode issue faced by a lot of vegetable growers across the State, according to Mr Long.
Nematodes are soil-born insects that feed on the root system of most crops and Nemat is designed to hatch onto the root system of the crop to kill off Nematode eggs so they can't multiply.
The security of consistent yields – 30 tonnes/ha over the past few years – has enabled MG Farm Produce to experiment with new potato varieties.
Working closely with a NZ company called Plant and Food, the Sheffield producers have developed their own tailored breeding plan.
Currently the company provides their own varieties of potato - Moonlight and Cream Delight - to the domestic market in Tasmania, but are looking to broaden the spectrum of what they can produce.
"People start jumping up and down because it's genetically engineered (new potato varieties), but there's a huge difference between genetically engineered and genetically modified," he said.
