FRUIT and vegetable growers have been urged to improve the health of their soils and boost the nutritional content of the food they grow.

Former Governor-General Maj-Gen Michael Jeffrey told more than 500 delegates at the recent inaugural AusVeg convention that growers must change the way they farm in order to head off a potential food security crisis.

Maj-Gen Jeffery, who is chairman of Outcomes Australia and an avowed fan of natural sequence farming, said it was time to adopt a more holistic approach to the management of animals, plants, soil and water.

"It is the responsibility of food growers to produce the best quality and most nutritious food possible," he said.

"Food retailers also need to ensure they market the best-value food possible and individual consumers need to be well informed about what they eat.

"We must eat well, but less."

Maj-Gen Jeffery called on AusVeg, as the vegetable industry peak body, to take the lead in reshaping the average Australian diet to include twice as many vegetables.

He said correct labelling was essential to enable consumers to make informed choices and take control of their own health.

And he urged the development of a "unified co-operative vision" to prevent further decline in the productivity of farming land, which he said had suffered from land clearing, excessive cultivation and irrigation, and reliance on chemical fertilisers.

"We know the nutrient densities, balances and thus the value of our foods have declined relative to those in wild foods, or compared with the same crops grown in healthy soils," he said.

"In the main, our agricultural philosophy has focused on yield, size and profit ... we have mined much of our soils of their natural plant nutrients."

Maj-Gen Jeffery said synthetic fertilisers had been unable to replace all the minerals needed for a healthy plant. And he expressed concern that adding vitamins to compensate for known nutrient deficiencies - as well as extra sugar, salt, fat, stabilisers, preservatives and flavourings - was contributing to obesity, diabetes and other health issues.

AusVeg chief executive Richard Mulcahy said Maj-Gen Jeffery had warned him beforehand that his speech would be provocative.

"Australia has some of the most nutritious and high-quality produce in the world," Mr Mulcahy said.

"Eating vegetables is one of the best things that an individual can do for their health and it is important that this is encouraged from an early age."