DES MOINES, Iowa - The United States and China agreed Thursday to sign a five-year deal that will guide discussions on food security, food safety and sustainable agriculture.

The agreement was announced at the first U.S.-China agriculture symposium in Iowa by Chinese Vice-President Xi Jinping, China Minister of Agriculture Han Changfu and U.S. Secretary of Agriculture Tom Vilsack.

Xi, who is expected to become China's next leader in a process that starts later this year, is on a U.S. visit this week that began with meetings with President Barack Obama and other officials. He was to fly to Los Angeles later Thursday.

Vilsack said the two nations will have to work together to help feed a growing global population.

"Current populations trends mean that we must increase agricultural production by 70 per cent in the year 2050 to feed nearly 9 billion people," he said.

Xi on Thursday discussed his visit to Iowa 27 years ago to learn about corn production and talked about the seven years he spent as a young man in a western China province working on farms.

"Agriculture, rural areas, and farmers have a special place in my heart," he said.