PASTURES and fodder crops have taken a battering in recent years from drought and weed infestations.

A recent field day in Victoria's North East looked at the consequences.

Four failed springs in a row have turned pasture management on its head for Numurkah dairy farmer Damien Carpenter.

    AT A GLANCE
  • Who: Damien Carpenter
  • What: dairy
  • Why: forage crops prove their worth
  • Where: Numurkah, Victoria

Moving from Tasmania to the Goulburn Valley in 2005, Damien has had to learn how to cope with drought.

"There has been a rapid change in how dairy farmers run their business," he said.

"We have seen 30 years of change in the past five years in the Goulburn Valley."

A qualified agronomist, Damien milks his 170-cow herd once a day, allowing him to work off-farm at Benalla.

"Forage crops have helped me get through the last two to three years," he said.

"My two biggest bugbears are silver grass and barley grass.

"I chose to control it with a forage rape."

Damien sowed greenland forage rape on an 8ha irrigated block and a 10ha dryland block as a comparison.

The irrigated pasture was direct drilled with 3kg/ha of seed and 10kg/ha of phosphorus on April 10.

An irrigation on April 20 was followed by an explosion of barley and silver grass.

Two grass herbicides were applied three weeks after sowing, along with 55kg/ha of nitrogen.

The crop was strip grazed from mid June to late August.

Damien said the forage rape was used as a substitute for feed concentrates.

"I chose this crop as it has a wide planting window, handles dry conditions and will respond to late rainfall in November and December," he said.

"It had a growing-season rainfall of 208mm plus 100mm of irrigation to give a total of 308mm.

"The cows grazed the rape during the day and were fed ryegrass pasture at night."

Damien used contractors for spraying, sowing and spreading, and estimated total establishment costs at $651/ha.

"This crop produced 8.4 tonnes of dry matter to the hectare on only one watering to give a water-use efficiency of 27kg of dry matter per millimetre," he said.

"Strip grazing resulted in 80 per cent utilisation to give a crop cost of $93/tonne dry matter (including water).

"It was a high-protein feed so it was a great substitute for concentrates."

On the dryland block, Damien planted the rape in place of canola in a barley-oats-canola rotation.

"It went in with some self-sown barley and ryegrass, which I wasn't game to get rid of as the season was so tough," he said.

The crop was direct drilled in May at 2kg/ha and germinated during the first week of June.

Trifluaralin was applied as a pre-emergent herbicide, 10kg/ha of P was applied at sowing, and 55kg/ha of N was applied two weeks after emergence.

The growing-season rainfall was 152mm to give a similar water-use efficiency of 25kg DM/mm.

The crop produced 3.9 tonnes DM/ha, with an establishment cost of $239/ha.

"The cost on 80 per cent utilisation worked out at $76/tonne DM on country that would generally be labelled as useless," Damien said.

"I had to manage pugging but it was a minimal problem. Forage rape is a crop which I could safely say will give me a feed every year."

Damien said the rape had extended his grazing rotation and saved him from buying in feed from elsewhere.