Soybean prices rose sharply Monday as hot weather lingered in the Midwest.
Corn prices also rose, as did wheat.
Gold and silver rose after Secretary of State John Kerry stepped up pressure on Syria, denouncing an attack there last week as a "moral obscenity" because of the widespread evidence that chemical weapons were used.
Energy prices ended mostly lower.
Soybeans for November delivery jumped 61.5 cents to $13.895 a bushel. 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, but in evening trading it rose $8.50 to $1,404.30 an ounce, crossing above $1,400 for the first time since June.