ST. LOUIS (AP) — Nearly 220 counties in a dozen drought-stricken states were added Wednesday to the U.S. government's list of natural disaster areas as the nation's agriculture chief unveiled new help for frustrated, cash-strapped farmers and ranchers grappling with extreme dryness and heat.

The U.S. Department of Agriculture's addition of the 218 counties means that more than half of all U.S. counties — 1,584 in 32 states — have been designated primary disaster areas this growing season, the vast majority of them mired in a drought that's considered the worst in decades.

Counties in Arkansas, Georgia, Iowa, Illinois, Indiana, Kansas, Mississippi, Nebraska, Oklahoma, South Dakota, Tennessee and Wyoming were included in Wednesday's announcement. The USDA uses the weekly U.S. Drought Monitor to help decide which counties to deem disaster areas, which makes farmers and ranchers eligible for federal aid, including low-interest emergency loans.

To help ease the burden on the nation's farms, Agriculture Secretary Tom Vilsack on Thursday opened up 3.8 million acres of conservation land for ranchers to use for haying and grazing. Under that conservation program, farmers have been paid to take land out of production to ward against erosion and create wildlife habitat.

"The assistance announced today will help U.S. livestock producers dealing with climbing feed prices, critical shortages of hay and deteriorating pasturelands," Vilsack said.

Vilsack also said crop insurers have agreed to provide farmers facing cash-flow issues a penalty-free, 30-day grace period on premiums in 2012.

As of this week, nearly half of the nation's corn crop was rated poor to very poor, according to the USDA's National Agricultural Statistics Service. About 37 percent of the U.S. soybeans were lumped into that category, while nearly three-quarters of U.S. cattle acreage is in drought-affected areas, the survey showed.