SQM abandoned hope of a rise in potash prices this year, amid a week which has seen one rival idle two mines, shares in another competitor halve, and prices of the nutrient "collapse".
The Chilean-based fertilizer and iodine producer forecast that its potash sales prices would this year "be lower than average prices in 2015", extending a decline which saw values last year fall by 7.7%.
"The main concern in this market is the significant decrease in prices that we have seen in the last few quarters," SQM said.
SQM's average potash sales price in the October-to-December period was 27% down year on year, and "prices in the first part of … have continued to fall," said Patricio de Solminihac, the SQM chief executive.
The comments come as data from Credit Suisse and Raymond James showed potash prices continuing to fall, hitting $215 a tonne in Brazil, where SQM makes one-third of its sales, but where appetite for imports has been undermined by the weakness of the real.
"Prices continue to collapse," said Raymond James, estimating Midwest US values down 7.4% over the past month to $284 a tonne.
Brazilian values are down 12% over the past month, according to Credit Suisse, although South East Asian values have shown a smaller decline, of 5%, to $265 a tonne
The latest drop follows reports of a halt on imports by India, the second biggest buyer of the nutrient, while top-ranked purchaser China is believed to be sitting on large stocks which are allowing it to delay an annual pricing round which sets a global benchmark.
Prices have fallen so far that some Canadian producers are believed to have offered potash at below production costs.
"I think that one of the Canadian producers… was extremely aggressive," Bob Jornayvez, the chief executive and chairman of US-based Intrepid Potash said on Monday.
"I would imagine some of those tonnes, given where we think they went, had a negative margin."
The comments followed the release by results showing a net loss of $518.3m for the October-to-December quarter, and in which the group's auditor raised doubts over the company's ability to stay in business – prompting a 55% slump in Intrepid Potash shares on the day.
The stock fell further on Tuesday, ending at a record closing low of $0.6688, down 70% over the two sessions.
In a further sign of the stresses in the industry, Canada's PotashCorp, saying it was "adjusting inventory", has unveiled four-week production stoppages at two mines, Allan and Lanigan.
The move follows the announcement in November of the closure of the Penobsquis mine in New Brunswick, and of temporary stoppages at three mines in Saskatchewan,
In January, PotashCorp revealed it was "indefinitely" halting operations at its Picadilly mine in New Brunswick in response to falling potash demand and weakening prices.
The company is "desperately trying to stop the rot" in potash prices, said commodities commentator Mark Latham, adding that the "industry, unfortunately, looks sick".
"The best we can say - we're less bearish than usual" on PotashCorp shares, which are "trying to form a base after a 50% fall in the last 12 months".
SQM's comments came as the group unveiled a 43% fall to $44.6m in earnings for the October-to-December quarter, on revenues down 16.3% at $411.3m.
Revenues in potash fell by 35% to $96.4m, undermined by the knock-on effects of production disruptions earlier in the year, as well as by price falls
"As we look to 2016, we will continue to see challenges in pricing in some of our major business lines," Mr de Solminihac said.
However, in lithium, "we believe that average prices in this business line will be higher in 2016".
And in potash, a return to normal production rates should allow a 20% rebound in sales volumes.
By Mike Verdin