CANBERRA: Chicago soybean and corn futures fell on Tuesday and were near three-year lows, as forecast of rainfall in South America bolstered expectations of ample supplies.

Wheat slipped as declining Russian grain prices maintained pressure on the market.

The most-active soybean contract on the Chicago Board of Trade (CBOT) was down 0.3% at $11.89-1/4 a bushel by 0324 GMT, just above last week’s low of $11.79.

CBOT corn fell 0.2% to $4.29-1/2 a bushel and was a whisker from a lows of $4.28 reached on Monday and last Friday.

“We still have an enormous amount of unsold soybeans coming into the market from South America,” said Ole Houe at agriculture brokerage IKON Commodities, adding that prices were likely to fall further.

The U.S. Department of Agriculture (USDA) cut its Brazilian soy harvest forecast last week by a smaller amount than expected and raised its global supply projection to the highest on record.

Brazilian beans are “trading at a sharp discount to the U.S. market as abundant supplies flow to export terminals”, said StoneX analyst Arlan Suderman.

Soybeans, corn hover near 3-year lows as speculators bet on lower prices

Argentina is also expected to see a bumper harvest, with widespread rains over the weekend boosting confidence in that forecast.

And demand in top importer China is weakening as a shrinking pig herd reduces demand for animal feed.

Speculators hold large net short positions in Chicago soybeans and corn but were net buyers of both on Monday, traders said.

For corn, consultants AgRural raised their forecast for Brazil’s 2023/24 second crop to 91.2 million metric tons from 86.3 million tons.

CBOT wheat fell 0.5% to $5.94-3/4 a bushel but was still some way above last September’s three-year low of $5.40.

Export prices in Russia, the biggest wheat exporter, fell again last week, the IKAR agriculture consultancy reported.