DES MOINES, Iowa - China and the United States should strengthen cooperation in trade and food security and further exchanges in technology and information, Vice-President Xi Jinping said at the first China-US Agricultural Symposium on Thursday.

"It will have great significance and far-reaching influence if the cooperation between the two large agricultural countries can rise to a strategic level in order to achieve mutual benefit and shared progress," he said at the symposium.

During the symposium, US Agriculture Secretary Tom Vilsack and China's Minister of Agriculture Han Changfu signed a five-year Plan of Strategic Cooperation to guide discussions on food security, food safety and sustainable agriculture.

"Agriculture is the highlight of the bilateral trade and Chinese government always pays great attention to this sector," Han said.

"This plan builds on the already strong relationship our nations enjoy around agricultural science, trade and education. It looks to deepen our cooperation through technical exchange and to strengthen coordination in priority areas like animal and plant health and disease, food security, sustainable agriculture, genetic resources, agricultural markets and trade, and biotechnology and other emerging technologies," Vilsack said.

Last year, China became the top market for US agricultural goods, purchasing $20 billion in US agricultural exports. The high total of exports to China helped to support more than 160,000 American jobs on and off the farm in 2011 across a variety of sectors, according to the US Department of Agriculture (USDA).

China imported 1.68 million tons of corn from the US last year, the highest figure in 15 years, according to the USDA. China imported a total of 1.75 million tons of corn that year.

"The agricultural trade development between the two countries has maintained a strong momentum in recent years" Xi said.

Over the past decade, bilateral trade volume has grown annually by 20 percent, he said.

On Wednesday, major Chinese companies, including COFCO Co Ltd, the country's largest State-owned grain trading house; and Sinograin, which manages China's grain reserves, signed deals in Des Moines with major food production companies Archer Daniels Midland, Bunge Ltd, and Cargill, among others.

The Chinese delegation was expected to sign more purchasing deals in Los Angeles on Thursday, which would bring the total amount of agricultural exports to a record of more than 12 million tons, said Kirk Leeds, CEO of the Iowa Soybean Association.

The soybeans will come from last fall's and this spring's harvests. The value of the purchases will be around $6 billion.

"China attaches great importance to food security, and ensuring a sufficient food supply for 1.3 billion people," Xi said.

He stressed that the two nations need to strengthen cooperation in technology to improve agricultural productivity and establish a fair market to enhance trade ties.

If China and the US can further cooperation in agriculture, it will help stabilize domestic economic operation and give a boost to the global economic recovery, he said.

According to the US Chamber of Commerce, 95 percent of the world's consumers and 73 percent of the world's purchasing power live outside of the US, with a significant portion of each tied to the Chinese economy, Iowa Governor Terry Branstad said.

"These are statistics which we cannot ignore as a state or nation."

In March, Iowa Lieutenant Governor Kim Reynolds and state Secretary of Agriculture Bill Northey will lead an eight-day trade mission to China to explore business opportunities.

China Daily