Soybean prices rose sharply Monday as hot, dry weather threatened crops in the Midwest.
Corn prices also rose Monday, as did wheat.
Gold and silver are rising after Secretary of State John Kerry stepped up the pressure on Syria, denouncing an attack there last week as a "moral obscenity" because of the widespread evidence that chemical weapons were used. Precious metals prices tend to rise when traders shift money into safe-play assets during times of escalating global tension.
Soybeans for November delivery jumped 61.5 cents to $13.895 a bushel.
Brandon Marshall, commodity trader with Northstar Commodity in Minneapolis, said that some parts of the Midwest soybean-growing region have only gotten about half the rainfall they usually receive this time of year, making growing conditions difficult. That could lead to smaller harvests and tighter supplies, pushing prices higher.
"It's just a lot hotter, and you're at a key stage with the beans now," Marshall said. "About 25 percent of the growing area in the Midwest is dry."
December corn rose 30.5 cents to $5.005 a bushel. December wheat rose 20.75 cents to $6.6675 a bushel.
Gold for December delivery ended the regular trading session down $2.70 at $1,393.10 an ounce. In evening trading, though, it crossed above $1,400 for the first time since June, rising $8 to $1,403.80 an ounce.
Silver rose to the highest point in three and a half months. The September contract closed the regular trading session up 27.2 cents at $24.01 an ounce, but in evening trading it rose 57 cents to $24.31.
Other metals were mixed.
Copper for September delivery fell 2.9 cents to $3.3195 a pound. Platinum for October delivery rose $2.90 to $1,544.50 an ounce and September palladium fell $4.80 to $746.05 an ounce.
Energy prices ended mostly lower.
Crude oil for October delivery fell 50 cents, or 0.5 percent, to $105.92 a barrel in New York.
Heating oil fell 1.6 cents to $3.08 per gallon, natural gas rose 3.2 cents to $3.55 per 1,000 cubic feet and wholesale gasoline fell 3.6 cents to $2.83 per gallon.