New York: A stronger dollar and weakening demand are sending prices for commodities lower again.

The ICE Futures US dollar index, which measures the dollar against a basket of other currencies, rose 0.5 per cent on Friday as investors seeking to reduce their exposure to risk parked more funds in dollars.

"The dollar is driving trading," said George Gero, vice-president at RBC Global Futures.

Commodities tend to fall when the dollar rises since it makes the contracts more expensive for foreign buyers.

Copper prices tumbled as traders feared demand from China could wane as that country taps the brakes on its economy. Energy prices also fell on signs that consumption of gasoline and other petroleum products remains weak.

Copper for March delivery fell 4.55 cents to $3.0525 a pound. Copper sold off for much of the week as China reins in its overheated economy by curbing bank lending and raising interest rates.

Weak demand was also dragging down energy prices. The Energy Information Administration said on Wednesday appetite for petroleum products has dropped four straight weeks.

Oil falls

Benchmark crude for March delivery gave up 75 cents to settle at $72.89 a barrel on the New York Mercantile Exchange.

In other Nymex trading in February contracts, heating oil fell 1.62 cents to $1.9029 a gallon and gasoline lost 1.43 cents to $1.9031 a gallon. The March contract for natural gas was higher for most of the day but settled down 0.007 cents at $5.131 per 1,000 cubic feet.

Platinum and palladium bucked the downward trend.

The metals, which are used in making catalytic converters in cars, have been rising in recent days on signs that auto production will ramp back up in the coming months.

Upbeat earnings from Ford Motor and news that Toyota was working quickly to resolve its gas pedal problems should mean auto production will rise, Gero said. Toyota has shut down plants and recalled about 4.2 million cars because of problems with gas pedals.

Platinum for April delivery rose $12.10 to settle at $1,506 an ounce. Palladium for March delivery was higher for nearly the whole day before a late drop left it down 70 cents at $412.65 an ounce.

Gold for February delivery fell 60 cents to settle at $1,083.80 an ounce. The April contract also settled at $1,083.80, down $1.

Sugar rose for the second straight day after a brief sell-off during the middle of the week. Contracts for March delivery climbed 0.90 cents, or 3.1 percent, to settle at 29.90 cents a pound.

Grains prices all fell. Wheat for March deliver fell 13 cents to $4.74 a bushel. Soybeans fell 17.75 cents to $9.140 a bushel, while corn fell 5.25 cents to $3.565 a bushel.

Frozen orange juice concentrate, cocoa and cotton all fell.