Cotton rose, capping the biggest two-day rally since March, on signs that persistent drought will slash production in the U.S., the worldΆs biggest exporter.

About 41 percent of cotton crops as of July 24 were in very poor or poor condition, compared with 8 percent a year earlier, U.S. Department of Agriculture data show. In Texas, the largest grower, 59 percent got the lowest rankings. On July 12, the USDA cut its forecast of domestic production more than analysts expected to 16 million bales from 17 million in June. A bale weighs 480 pounds, or 218 kilograms.

Unusually hot, dry weather across the southern U.S. “could possibly be devastating” to a crop that may tumble below 15 million bales, Louis Barbera, a broker with VIP Commodities in New York, said by telephone.

Cotton for December delivery climbed 2.85 cents, or 2.8 percent, to settle at $1.0361 a pound at 2:34 p.m. on ICE Futures U.S. in New York. The price surged 7.1 percent since July 25, the biggest two-day rally since March 18. The fiber, up 35 percent in the past year, reached a record $2.197 on March 7.