Monday didn't start off as exactly the busiest day on agricultural commodities, with the benchmark US markets closed.

But what movement there was was mixed, despite the broadly improved sentiment towards many risk assets for 2013, which has been underpinned by optimism over US and Chinese economies.

It has to be said that there are nuances in the idea of a "risk on" theme, with some assets being preferred over others.

"I continue to question the overall fund involvement in the ag sector as multi-year highs in the equity futures and solid upward momentum in the energy complex have the potential to take preference over the ag sector," Kim Rugel at Benson Quinn Commodities said.

After all, ags "didn't treat them very well in 2012", she added, uncertain "whether or not the trade is ready to commit to holding new length at these prices".

Speculators return

But the US Department of Agriculture cuts 10 days ago to estimates for domestic corn and wheat stocks at the close of 2012-13 have allowed grains, and oilseeds, to make up for a poor start to 2013.

Indeed, managed money, a proxy for speculators, put on a stack of long positions on the grain in the week to last Tuesday, latest regulatory data showed.

The net long in Chicago futures and options rose 26,736 lots over the week, the Commodity Futures Trading Commission said late on Friday.

In soybeans, speculators raised their net long position by more than 6,000 contracts.

Soybeans vs grains

Chinese markets, which were open on Monday, reflected thos better sentiment, with Dalian soybeans for May rising 0.5% to 4,827 yuan a tonne, while May soyoil added 0.9% to 8,714 yuan a tonne.

But grains proved less robust, with corn falling 0.3% to 2,457 yuan a tonne, and May wheat on the Zhengzhou falling 0.9% to 2,563 yuan a tonne.

Also to factor in to Chinese prices were import data for 2012, for which the headline was of huge corn imports, which near-trebled to 5.2m tonnes, an all-time high, and rice, for which they quadrupled to 2.3m tonnes, also a record.

For wheat, the rise was of 195% to 3.69m tonnes, the highest for eight years.

However, the December data itself was not so strong for grains, falling 53% to 266,000 tonnes for corn, while heat's halved to a nominal 5,527 tonnes.

Palm import data less bad

The firm performance in Dalian soyoil also fed through into the market for palm oil, of which China is a major importer – especially in the run-up to the Lunar New Year festivities starting next month.

Although have Chinese importers restocked already? Data from cargo surveyor SGS showed Malaysia's palm oil imports down 19.9% so far this month, from the same period of December.

Rival Intertek put the drop at 17.3%

Stlll, these were at least improvements of mid-month figures of a 22% drop, according to SGS, and 20.7% decline, as measured by Intertek.

Kuala Lumpur palm oil for April gained 0.6% to 2,414 yuan a tonne

Rubber's bounce

Elsewhere, in Tokyo, rubber for June eased 0.3% to 310.60 yen a kilogramme, a decline attributed to profit-taking after a falling yen boosted hopes for Japanese exports of goods including cars.

Rubber remains amongst its highest levels for nine months, and up 50% from tis August 2012 low.

At Phillip Futures, Ker Chung Yang also cited the role of improved Chinese growth ideas in boosting the tyre-ingredient, with China the top importer.

Still, natural rubber imports last month were reasonable but not huge, at 211,351 tonnes, up 3.2% from December 2011, a little below the overall rate of increase in 2012 of 3.6%.

(Interestingly, synthetic rubber imports fell 9.8% last month and 0.5% over 2012 as a whole, reflecting relatively low natural rubber prices.)

Import retreat

However, Chinese sugar imports showed a steeper decline last month, of 46% to 268,362 tonnes, contrasting with a rise of 28% over 2012 as a whole, and appearing to bear out ideas of a reduced need for foreign supplies following strong domestic beet and cane harvests.

(Associated British Foods on Friday forecast a drop in its Chinese sugar profits this year, thanks to reduced prices stemming from better production.)

Zhengzhou sugar for May fell 0.9% to 2,563 yuan a tonne.