( CNN ) -- More than half of all U.S. counties have been designated disaster zones , the Department of Agriculture reported , blaming excessive heat and a devastating drought that 's spread across the Corn Belt and contributed to rising food prices . Agriculture Secretary Tom Vilsack declared disaster zone designations for an additional 218 counties in 12 states Wednesday because of damage and losses caused by drought and excessive heat . The states are Arkansas , Georgia , Iowa , Illinois , Indiana , Kansas , Mississippi , Nebraska , Oklahoma , South Dakota , Tennessee and Wyoming . Nearly three-quarters of the nation 's cattle acreage is now inside a drought-stricken area , as is about two-thirds of the country 's hay acreage , the agency reported . Iowa farmers looking beyond drought . USDA researchers added that an average of 37 % of the nation 's soybeans were last week ranked from very poor to poor , the lowest quality recorded since a massive drought in 1988 . Nearly half of America 's corn crop was also rated very poor to poor , while 57 % of its pastures and range land were similarly graded . This year 's harsh conditions suggest that food prices next year could surge by as much as 4.5 % , the agency reported . `` It 's the most severe and expensive drought in 25 years , '' USDA economist Timothy Park said . As the hot and dry weather persists , farmers face potential losses in spite of federal crop insurance meant to soften the blow to U.S. agriculture . `` The pocketbook is really taking a hit , '' said Robert Dickey , a 58-year-old farmer in Georgia who says his losses are just below the threshold needed for his insurance to kick in . `` We 'll probably have to take out some loans to get us through to next year . '' Interactive map : Record dryness takes over the U.S . The price of milk , cheese and other dairy products is also expected to surge , while ranchers face steepening feed costs . `` When I was a kid in the '50s ... it got real dry , but nothing like this , '' said Marvin Helms , a 70-year-old farmer and rancher in central Arkansas who was compelled to sell his beef cattle after being short on feed . His thousand acres of farmland near Arkadelphia include corn and soybeans , which Helms says is normally sufficient to sustain his family and provide for his cattle . Farmer in the drought : If you plant it , it may not come . `` We 've got some insurance on the crops , but it 's not enough , '' he said . `` It will help , but it wo n't pay the bills . '' Still , economists say the extent of federal insurance coverage -- which includes about 85 % of the nation 's crop acreage -- will help protect farmers against catastrophic income losses . `` Today 's safety net is going to protect a lot more of those producers than in the past , '' said USDA Deputy Chief Economist Robert Johansson . `` Though it 's hard to say the what effect will be on an individual producer , because a lot of times , these crop producers are also producing livestock . '' Food prices on the rise . In an effort to bolster assistance , the USDA expanded emergency disaster assistance Wednesday to allow for haying and grazing on 3.8 million acres of protected conservation areas , once considered off-limits . The agency also reported that crop insurance companies have agreed to allow for a `` short grace period for farmers on insurance premiums in 2012 , '' giving farmers an extra 30 days to make payments without interest penalties on their unpaid premiums . But while a variety of crops are strained across the U.S. Midwest , a top concern for policy-makers is corn . `` The unusually hot and dry conditions coincide with the period of pollination and kernel formation , which sharply reduces estimated yields , '' the USDA reported . `` As of July 17 , approximately 88 percent of the corn crop was in regions impacted by drought . '' About 75 % of all food found in the supermarket contains corn , officials say . See all of our coverage of this year 's drought . Is the drought affecting you ? Share with us on CNN iReport .
NEW : `` Safety net is going to protect a lot more of those producers , '' economist says . An Arkansas farmer says he was compelled sell his cattle because he was short on feed . Harsh conditions suggest food prices could increase as much as 4.5 % in 2013 , agency says . Agriculture secretary expanded emergency disaster assistance Wednesday .