Commodity prices slide to lowest level in a generation

Lower fuel prices are compounding the longest commodity slump in a generation.

Because energy accounts for as much as half the cost to produce food and metals, all sorts of commodities will keep dropping, according to Societe Generale SA and Citigroup Inc. With inventories ample and slowing economies eroding demand, cheaper oil lowers the price floor for mining companies and farmers to remain profitable.

Corn may drop another 3 percent, cotton 6.5 percent and gold as much as 5 percent, SocGen estimates.