NEW YORK—Gold closed lower for a fourth straight session Wednesday as another drop in crude prices coupled with a stronger dollar diminished the metal’s appeal as a safe-haven asset.

Other commodities traded mostly lower, with corn hitting a four-month low and soybeans also falling sharply.

Gold has faced strong downward pressure in recent weeks — dropping 5 percent in the past month — as dwindling demand for energy and a weakening U.S. economy cuts into the price of crude and other commodities.

Further weighing on prices, the dollar has gained ground in rec...