Dave Lewis, grains account manager with PIRSA, says warmer temperatures through May and June, and good rainfall, meant crops have established well, reports ABC Rural.
"I can't recall in the 20 years I've been associated with putting the report out that we've put an estimate out this early, for such a crop to be so well above average, so it's really reflecting quite an outstanding start to the season."
Mr Lewis says the state is on track to plant a 4.4 million hectare crop, which is around the same area that's been planted over the past 10 years.
"We're in an unprecedented place where we've had an ideal start, under near perfect timing, and a significant area of crop that's gone in."
But Mr Lewis says there are a few places around the state's mid-north, central regions and on Kangaroo Island which have suffered from waterlogging issues through June.
The long dry spell over much of the state during summer and autumn is creating problems for crops, because not enough nitrogen has mineralised in the soil Mr Lewis says because of this, many early sown crops are starting to show signs of nitrogen deficiency, especially on light sandy soils.
But the dry spell has also lowered the weed, disease and pest profile across the state. "For weeds, some of the crops were sown dry in April before the rains came, and they've established quickly.
"A lot of the farmers have used a herbicide to control the weeds in those particular crops.
"So we shouldn't really see significant problems with weeds."
