Tuesdays have a habit of bringing reversals in Chicago, as traders often say.
And this one was not an exception.
It was actually a tricky day for many markets, early on at least, with concerns over the Federal Reserve's withdrawal from asset purchases, part of its easy monetary policy stance, prompting pullbacks.
Shares tumbled 2.6% in Tokyo, and were down 2.0% in Hong Kong in late deals.
Many industrial commodities were under pressure.
That only encouraged selling in grains and oilseeds, as investors took profits on the strong rises in the last session, making it a proper Turnaround Tuesday.
Sure, the US Department of Agriculture overnight produced data confirming a deterioration in domestic corn and soybean crops.
The proportion of corn rated "good" or "excellent" fell by three points to 61%, with the soybean figure falling 2 points to 62%.
It was a particularly poor week for Missouri, which saw its soybean crop downgraded to 5 points in good or excellent ratings to 49%, with its corn rating slashed by 10 points to 47%.
But declining ratings had been factored in during the last session, when December corn futures added more than 4%, and soybeans 3% to retake the $13-a-bushel mark.
Besides being expected after dry weather, cuts in crop condition are barely unusual at this time of year.
"It is typical for the corn crop condition index to decline slightly from early July to mid-September, then increase into harvest," Mark Welch at Texas A&M University said, adding that a crop condition index derived from the USDA data was, at 361, a little above the average for this time of year of 356.
At Benson Quinn Commodities, Kim Rugel said that "crop ratings in line with expectations look to offer modest pressure to start of overnight session".
Furthermore, investors got another reminder that, while the weather outlook is too dry to be ideal, crops are hardly in poor shape with the first data from the ProFarmer crop tour, which showed the South Dakota corn yield at 161.75 bushels per acre, up from an average of 119.65 bushels per acre, and a 2012 finding of 74.26 bushels per acre.
The Ohio yield was pegged at 171.6 bushels per acre, above an average of 144.1 bushels per acre, and last year's 110.5 bushels per acre.
For soybeans, the tour found an average South Dakota pod count of 1,016.7 per plot (3 feet x 3 feet), nearly twice last year's figure (584.9) and above the three-year average of 984.6 pods per plot.
In Ohio, the pod count, at 1,283.6 pods per plot, was ahead of a 2012 figure of 1,033.7 pods per plot, and an average of 1,162 pods per plot.
Margin for error
Sure, the tour results are hardly flawless.
"Last year, Pro-Farmer underestimated the corn crop by 300m bushels and soybeans by a whopping 415m bushels," US Commodities noted.
"They were much closer on 2008 and the 2011 crops, but underestimated the final corn production in 2009 by 150m bushels and 2010 by 300m bushels."
Still, with soybeans, at least, looking technically overbought too, there was enough doubt over further prices for investors to feel confident in provoking a price reversal.
Chicago corn for December fell 1.3% to $4.79 ¼ a bushel as of 09:40 UK time (03:40 Chicago time), and soybeans for November 1.3% to $12.86 ½ a bushel.
As for whether a more significant reversal is in the works, "trade will need to see rains before a more significant technical correction can be seen," Ms Rugel said.
'Export market may decline'
Row crops' performance weighed on wheat too, which has turned into something of a follower in Chicago.
There, the September soft red winter wheat contract fell 0.7% to $6.36 ¾ a bushel, despite the strong US export data on Monday, showing weekly shipments, as measured by cargo inspections, of 33m bushels, well ahead of expectations.
That did not quell concerned over the competitiveness of US wheat.
"The US export market may decline" with many traders "concerned if US wheat was cheap enough to be able to compete with countries in the Black Sea region", Joyce Liu at Phillip Futures said.
However, spring wheat took some succour in a slow rate of harvest progress, with 18% of the crop in the barn as of Sunday, 20 points behind normal, according to the USDA crop progress data released overnight.
Crop condition was steady at 66% good or excellent, with Minneapolis-based Benson Quinn Commodities noting talk generally of "good yields and good quality overall".
"Protein in many areas is a little low compared to normal, but not always as low as some had feared."
Minneapolis spring wheat for September stood unchanged at $7.45 ¼ a bushel.
Among soft commodities, cotton tumbled 1.1% to 91.87 cents a pound in New York for December delivery after the USDA said that the condition of the US crop improved in the week to Sunday, by three points to 46% good or excellent.
In Texas, the top US cotton producing state, the crop improved 4 points to 35% good or excellent, thanks to rains.
"Most areas of the state received rain last week, while areas of the Plains and the Upper Coast received 2 inches or more," USDA scouts said.
The overall improvement surprised many investors who have focused on the dismally wet conditions in much of the south east.
Cotton in Alabama continued to decline, dropping three points, albeit to a still decent 63% good or excellent.
In the coffee market, arabica prices fell 0.7% to 121.85 cents a pound for December delivery in New York, while robusta values dropped 0.7% to $1,863 a tonne in London.
The declines come amid weakness in Vietnam's cash market, where merchants are offering some 39.000 dong per kilogramme for robusta beans, the lowest price since July 10.
Vietnam is the top robusta-producing country.