This volatility will be particularly true for grain and oilseeds markets, with a supply squeeze in the first six months expected to push prices higher, before an expected production rebound leads to a weakening in prices in the second half of the year.

"Weak global economic growth and continued macro uncertainty may cause a slight drag on demand for agricultural commodities in 2013; however, a low US dollar will provide support for prices," said Luke Chandler, Global Head of Rabobank's Agri Commodity Markets Research (ACMR). "Speculative money flows will also remain very sensitive to macro uncertainties with the risk-on/risk-off trading pattern of 2012 likely to continue. Using the S&P Agri Index as a proxy for our commodity forecasts, we expect a decline in agricultural prices of around 10% between Q1 and Q4 of 2013."

The report says soymeal is the commodity likely to show the largest price decline by the end of 2013. In contrast, Rabobank analysts expect palm oil to be the strongest performer, as Chinese imports and biofuel demand drive prices higher after the sell-off in 2012. The soft commodity markets should continue in the same vein as this year, with prices expected to be relatively range bound.

Grain and oilseed prices - corn, wheat, and the soy complex - are forecast to rally in the first quarter of 2013, as a supply squeeze builds pressure and prices are forced higher to ration demand. Current use levels - particularly for corn, wheat and soybeans - appear to be running too fast given the sub-optimal 2011/2012 crops in both the US and South America.

Higher prices early in the year will also encourage record plantings of row crops in the US during 2013. Prices are expected to fall in the second half of 2013 as production rebounds, shifting fundamentals into a small surplus. However, lingering drought in the US remains a key risk to this surplus and to consequent production and price forecasts for the year.

Rabobank's outlook for soft commodity markets - sugar, cocoa and cotton - is neutral to slightly bearish in 2013. Fundamentals in soft commodities are more balanced, and in some cases (e.g. sugar and cotton), surpluses have been built over recent seasons. Despite the support of a weaker US dollar, some soft commodity prices are forecast to fall to multi-year lows in 2013.

Record coffee, cotton and sugar crops in 2011/2012 resulted in strong downward corrections in 2012, meaning that the softs have already moved through the cycle expected for grains and oilseed in 2013. The softs markets have now fallen near levels which Rabobank deems as fair value, with expected unwinding of investor short positions and commercial buying to keep markets flat or supported throughout 2013.

Rabobank's 2013 Predictions

• Cocoa - Cocoa prices are expected to move sideways to slightly higher in 2013 amid tightening fundamentals.
• Coffee - Coffee prices are expected to increase in 2013 finding support from increasing global demand and tightening stock levels.
• Corn - We expect CBOT corn prices to fall 24 per cent from Q1 2013 to average $6/bushel in Q4 2013 during the US 2013/14 harvest. Despite the bearish outlook, the beginning of 2013 is expected to see prices rise from current levels to encourage further demand rationing in the US.
• Cotton - Global cotton prices are forecast to plateau in 1H 2013, as the market faces its largest ever period of oversupply, before the curve lifts modestly by year end.
• Palm Oil - Palm oil prices are forecast to rise in Q1 2013 as stocks are drawn down from record high levels, before falling later in the year as palm oil and soybean output rebound.
• Soybeans - Soybean prices are expected to remain supported in Q1 2013 on tight export supplies before declining as production rebounds later in the year, with prices for the year averaging below 2012 levels.
• Soymeal - CBOT soymeal prices are likely to drop by nearly $75/ton from current levels by the end of 2013 as demand slows.
• Soy Oil - Soy oil prices are forecast to remain rangebound at the beginning of 2013 on high US supplies, before increasing in mid-2013 as supplies are drawn down.
• Sugar - Sugar prices (ICE #11 contract) are forecast to ease 5 per cent over the next 12 months as world sugar supply reaches a net surplus of 5.9 million tonnes.
• Wheat - CBOT wheat prices are forecast to rise to $9.10/bushel in Q1 2013 and then fall 23 per cent to $7.00/bushel by Q4 2013.