For one agricultural commodity, anyway, the coincidence of holidays in many of food and farming's major powers, such as Brazil and China, provided some support.

That was sugar. The absence of Brazilian producers, sidelined from selling by carnival celebrations, was seen as behind a rise of 1.7% to 18.44 cents a pound in New York raw sugar futures, for March delivery, their first rise in six sessions.

This pulled the sweetener back above their lowest close since August 2010, on a spot contract basis.

'Overdue for a pullback'

Other agricultural commodity markets found headway harder, even New York arabica coffee, for which Brazilian selling has been seen as a major negative too.

Still, there was some optimism over prospects, even at the close, when Sucden Financial forecast that arabica futures were "probably overdue for a pullback".

"One would imagine that roasters would be happy to step in and begin to buy at these prices. So while the 142.60-cents a pound support [for the May lot] remains we could be in for a move up in the near future," the broker said.

The May contract, the best-traded by a small margin, actually closed down 0.6% at 141.05 cents a pound.

'Harvesting to step up'

But in Chicago, holidays only emboldened sellers, with China's lunar new year holiday week, celebrated in some other countries too, keeping at bay a major buyer of the likes of soybeans.

And bears had other reasons too to assume the advantage, such as Goldman Sachs downgrading forecasts for prices of corn, soybeans and wheat.

The US Department of Agriculture, in preliminary estimates, forecast significant rebuilds in US corn and soybean stocks in 2013-14, backed by better yields, rather than higher sowings. 

Weather is improving for soybeans, and corn, in South America too.

In central Brazil, overabundant rains - which continued over the weekend in the likes of Mato Grosso, sapping progress of the early harvest – "should ease a bit in northern areas, allowing harvesting there to finally increase a bit", weather service MDA said.

In southern Brazil, where too little moisture has been the problem, "rains are expected to build across south central areas this week, which should improve moisture for late soybean growth especially in Parana, Santa Catarina, and Rio Grande do Sul", MDA said.

'Significant rain'

Meanwhile, Argentina received bigger-than-expected rains over the weekend.

And more is on its way, with weather models turning wetter in their outlooks, if by differing degrees.

"The European model continues to bring significant rain with excellent coverage to much of central, eastern, northern Argentina in the six-to-10 day period," weather service WxRisk.com said. 

"The GFS model has some rain in these areas but not nearly as much and with less coverage."

'Fearful of export competition'

On the markets, Country Futures' Darrell Holaday noted that "a little unexpected rain in the Argentine production areas over the weekend seemed to set the overall tone with a lower market overnight".

And, as a further pressure on soybeans, weekly export data for the oilseed came in weaker, at 30.1m bushels, down from 55.9m bushels the week before, and 39.1m bushels a year before.

"The trade is fearful of continued export competition from South America on both soybeans and corn," broker US Commodities said.

"Ending stocks on US soybean and corn stocks remain historically tight. The trade, however, is looking past this for now and confident the competition will plug this void."

Then there were technical factors to bring in, such as soybeans' fall in two sessions from above all their major moving averages to below.

Chicago's March soybean lot closed down 1.4% at $14.31 ½ a bushel.

Ethanol help

Chicago corn felt many of the same pressures, and ended up, for March delivery, closing below its 200-day moving average for only the second time since June.

In its favour nonetheless was some recovery in US exports, as measured by cargo inspections, coming in at 14.5m bushels, more than twice the level of the week before (if half the shipments in the same week of 2012).

In fact, the Chicago corn market "is going to have lean on domestic demand as only incremental up ticks in global demand for US corn are expected on the lower prices", Benson Quinn Commodities said.

"The possibility of ethanol plants coming back on line due to better profit margins is a positive for the corn market longer term."

Corn fell, but not as far as soybeans, dropping 0.9% to $7.02 ¼ a bushel, and for now holding on to the psychologically important $7-a-bushl mark.

'Virtually a joke'

In fact, in losses, it was also far eclipsed by wheat, which in Chicago tumbled to its weakest close since June last year, falling 2.0% to $7.41 ½ a bushel for March delivery.

The decline was blamed not only on broader selling, but on the rains which are easing some concerns over drought-hit areas, where wheat seedlings are struggling, and with more precipitation forecast.

OK, not all observers were convinced about the weekend precipitation.

"The storm system that moved through the hard red winter wheat area over the weekend was virtually a joke compared to what the model projections were showing early last week," Country Futures' Darrell Holaday said.

But there is "another upper level system that may bring some snow to southern Kansas and Oklahoma tonight or early tomorrow. That is resulting in some price pressure in wheat".

'Improve soil moisture'

MDA said that "rains favoured eastern Kansas, central and eastern Oklahoma, and east central Texas this past weekend, with snow noted in western Nebraska and north eastern Colorado".

"The upturn in snow across south western areas Tuesday will help improve soil moisture a bit once it melts," the weather service said, adding that the outlook for next week was a little wetter too.

Furthermore, analysis group Ikar downplayed ideas of huge Russian wheat imports, which have been murmured by some traders.

London wheat for May also fell, by 0.6% to £207.75 a tonne, but Paris wheat for March gained some support from position closing ahead of its expiry to end up 0.2% at E246.50 a tonne.

The May lot dropped by 0.4% to E240.50 a tonne.