RAIN has put a dampener on things in more ways than one as the annual grain harvest moves further south in Victoria.

Falls in the Wimmera and Mallee slowed the progress while torrential rain in northern NSW sparked fears of more downgraded grain coming on to the already well-supplied feed-grain market.

Barley growers are struggling to produce grain with the right protein and screenings to make lucrative malt grade, with some facing protein levels of up to 20 per cent.

And with global economic problems and a fluctuating Australian dollar, many traders are reluctant to offer cash prices at grain silos.

Wheat has dropped about $200/tonne since the highs earlier this year and barley by about $180/tonne since peaking late last year.

A dramatic fall in the Aussie dollar also saw some feed-barley prices drop $15/tonne late last week.

And lentils, which early this month were at historic highs, have dropped by up to $200/tonne in the past two weeks.

Out in the paddock results have been mixed with some farmers pleasantly surprised and others looking at yields that did not match the size of their stubbles. Warracknabeal agronomist Ian Glasgow said he'd seen few paddocks produce malt-grade barley with most producing feed 1 to feed 3 grades.

Mr Glasgow said good barley crops were yielding 1.6t/ha, which at current prices was barely covering the cost of production.

He said most people were storing on-farm or warehousing in the hope that prices would improve after harvest.

Colin Coates, from Traynor Lagoon, said barley in his area had yielded up to 1.8 tonnes/ha with many farmers producing 1.35 tonnes/ha.

"What we've got for seven inches (175mm) of rain is pretty good,"he said.

"A lot of people are surprised by how they have underestimated their yield."

Mr Coates said the November 13 start to harvest was one of his earliest.

"When I came home from school (to farm) we used to be out carting hay on Melbourne Cup Day and now we are getting ready to harvest," he said.

VFF Grains Group president Geoff Nalder said rain had delayed his harvest three times so far and he was now planning to leave barley and start on the wheat which was showing good test results.

Mr Nalder said less than 15 per cent of his barley had met malt specifications but some farmers in the Ouyen and Hopetoun areas had reportedly enjoyed better malting-barley results.

He said the world financial crisis was making it hard to find companies that put up their hand and buy grain.