So, all those concerns ahead of Washington's latest benchmark report on global crop and supply demand, and all that really mattered was the oil price.

Sure, the data, which cut US stocks by a little more than analysts had expected, had some impact on early deals in Chicago, as observers such as Benson Quinn Commodities forecast.

"This morning's USDA report will add additional support to soybeans and corn, with both US and world ending stocks seen declining month-on-month, [and] with US stocks below the average trade estimates," the US broker said.

But hopes that much bullish feeling would hang around were dispelled well within the first hour of trading, when March soybeans began the descent which would leave them at $9.24 ½ a bushel at the close, down nearly 20 cents from their intraday high, if a modest 2.5 cents down on Monday's close.

March wheat, which took a supporting role in the USDA report, closed lower too, down 1.75 cents at $4.82 ¼ a bushel.

Corn, however, went against the grain, adding 2.5 cents to $3.58 ½ a bushel.

Chinese whisper

Why so?  One reason is that it didn't have some of things going against it that soybeans did, such as the exit of its biggest buyer – China, in soy's case.

Vic Lespinasse, at GrainAnalyst.com, noted "widespread expectation that China will be out of the bean market all next week for their lunar New Year holiday, and [that] when they return more and more of their buying will be from South America rather than the US".

Indeed, Conab, Brazil's crop supply agency, raised its estimate for the South American country's ongoing soybean harvest by 1.6m tonnes to a record 66.7m tonnes.

Sure, that isn't that far from the 66.0m-tonne figure revealed by the USDA minutes later, but Conab does have a reputation for conservative estimates.

Crude control 

Another reason for corn's support was its use in making biofuels.

Oil, which dipped below $69 a barrel on Friday, had a stormer of a day, adding 2.5% t0 $73.71 a barrel on growing hopes of support for Greece, whose sorry public accounts were behind sell-offs in many markets last week.

(Indeed, many markets had a better day on Tuesday, with Wall Street's S&P 500 index up 1.5% heading into late trade. The euro recovered too to hit $1.3839 at one stage, more than 2.5 cents above Friday's low.)

"Higher crude oil means more demand for alternative fuels, such as bio fuels like ethanol made from corn or bio diesel fuel made from soybean oil," Mr Lespinasse said.

And it was notable that it was corn and soyoil which garnered buying, of 5,000 and 3,000 lots respectively, from funds which sold 3,000 soybean contracts and 3,000 wheat lots. These estimates were made with about half an hour trading yet to come.

And it was corn and soyoil, which added 1.1%, which closed notably higher.

'Flat, mixed-bag event' 

Would rapeseed follow the soybean or the soyoil in Europe? It owed more to the bean, ending down E0.75 at E288.50 a tonne in Paris for May delivery.

March wheat ended lower there too, down E0.50 at E125.50 a tonne, with weaker sterling credited for the helping London's equivalent close unchanged at £97.50 a tonne.

Hugh Schryver at Glencore's UK grain arm said: "The market was hoping for some form of inspiration. Unfortunately the USDA proved to be a flat, mixed-bag event."