Once again, a relatively calm performance by the CRB commodities index, which eased 0.2%, defied greater volatility in ags.

But this time it was soft commodities which clocked up the gains – for now, at least - while oilseeds and grains succumbed to a "stale news flow".

New York raw sugar for March set a two-year low, for a spot contract, of 18.06 cents a pound in early deals only to recover to end at 18.50 cents a pound, a gain of 2.1% on the day.

While acknowledging the depressant to prices from better-than-expected Brazilian sugar output in 2012-13, Standard Chartered analyst Abah Ofon flagged a "high risk of further demand pressure on China's domestic sugar stocks.

"In our estimation, the market is not sufficiently pricing for supply risks in 2013.

'Good support'

"We believe sugar prices are now hovering at the marginal cost of production which implies current levels are a good support," Mr Ofon added.

Nick Penney, at Sucden Financial also clocked technical support for the sweetener, in which speculators have already undertaken a stack of liquidation, besides the approach of the 17.50-cents-a-pound level at which it becomes more profitable for Brazil's mills to turn cane into ethanol instead of sugar.

"Whilst remaining overall bearish in the medium term, we are mindful of the market being oversold, of physical differentials firming, and of a substantial if not record short position" expected in forthcoming regulatory data, he said.

'Lower prices spark demand'

New York arabica coffee for March recouped some of their losses of the last session too, rebounding by 1.2% to 150.40 cents a pound, amid some profit-taking on short positions, but also some hopes for consumption.

"Differentials in Brazil and Colombia are rising as lower prices spark demand," Societe Generale noted.

However, the bank nonetheless attributed futures a mildly bearish rating, noting rising New York inventories, while Somar hardly did bulls a favour by flagging the benefit of recent rains to Brazilian plantations, where low rainfall last month had triggered some fall of immature cherries.

"With the return of moisture, the plants and the fruit returned to developing satisfactorily," the consultancy said, flagging improved prospects in parts of Sao Paulo, Parana and, in particular, Bahia, which has been in the grips of drought.

New York cotton for March defied some cautious comment too, from Australia & New Zealand Bank, to recover early losses and close 0.7% higher at 80.48 cents a pound, a fresh seven-month high for a spot contract.

'Stale news flow'

However, grains and oilseeds showed no such resilience, giving back some of their recent gains, in part because of nothing – that is, no fresh news around which to build a bullish case.

"Ag markets are leaking, with a stale news flow overshadowing the continued concern over net drying across southern Brazil and Argentina," Richard Feltes at RJ O'Brien said.

Furthermore, "nothing was reported on daily sales update today" from the US Department of Agriculture, which reports any major crop export deals, which traders are obliged to report.

This lack of export alerts "undermined rumours that China is booking February/March US soybean cargoes", Mr Feltes said. 

'Fast-moving front'

In fact, there was some movement on the dry Argentine weather outlook which has been a major support to row crop values of late.

"The weather this morning is slightly improved," US Commodities said, noting forecasts that half of Argentina is in for rainfall in the six-to-10 day window.

"At the end of this period about one-third of the area will remain dry versus an estimate of 50% yesterday."

Darrell Holaday at Country Futures said: "There is a fast-moving front that will move through on Thursday and Friday and that has taken some of the momentum out of today's trade."

Chart negatives

Meanwhile, the technical picture has deteriorated too.

Chart watchers in soybean took fright after Chicago's March lot foundered at its 75-day moving average in the last session, closing just below it (and further beneath it on Wednesday).

Corn suffered a similar setback in the last session, and added to its problems this time by closing back below its 50-day moving average, at a little over $7.32 a bushel.

It also faced a downbeat note from Societe Generale, which cautioned that high prices were rationing demand from US livestock farmers more than investors have appreciated.

In fact, corn did worst of Chicago's big three, ending down 1.1% at $7.20 ¾ a bushel, while soybeans for March ended down 1.0% at $14.37 a bushel.

Soybean snarl-ups

But then soybeans did gain some strength from the Brazilian rains which, even if welcomed by coffee farmers, are not so opportune for attempts to boost early harvest volumes and meet demand from importers which have for months been forced to pay up for dwindling US supplies.

In fact, Agroconsult cautioned that the waiting time for vessels expecting to load up in Brazil next month could approach 45 days.

Benson Quinn Commodities said: "The availability of early soybeans out of Brazil remains in question."

Wheat vs corn

That left wheat the strongest of a weak Chicago bunch, in falling 0.6% to $7.74 ¼ a bushel for March delivery.

It gained some support from its relatively low premium over corn, which it can replace in some functions, such as feed, in which it is considered a modestly more nourishing choice.

Furthermore, there are some concerns that the latest wave of Australian heat and dryness could hurt prospects for the next crop, although this has yet to be sown.

'Barometer for demand'

That, said "the US export picture for grains is weak and last week's European Union exports were comparably light too," Rory Deverell at FCStone said.

"The trade will now look to tomorrow's EU export licenses statistics as a barometer for demand and direction."

US wheat export sales are 12% down year on year, despite the low levels of stocks in many rival exporting countries (although that declines pales against the 56% drop in US corn export sales).

In Europe, Paris wheat for March closed down 0.6% at E251.50 a tonne, although London's May lot managed to close unchanged at £216.00 a tonne.