Chinese leader visits Iowa, Calif. to forge bonds LOS ANGELES (AP) - China's soon-to-be-leader arrived in California on Thursday to wrap up his four-day U.S. trip by talking business with Gov. Jerry Brown, touring a shipping terminal at the giant Port of Los Angeles and maybe even catching a Lakers game. As with his previous travels, Vice President Xi Jinping was focusing on forging relationships. Xi spent the morning in Iowa, where officials from the U.S. and China signed a five-year deal to guide discussions on food security, food safety and sustainable agriculture. China became the top market for U.S. agricultural goods last year, purchasing $20 billion in U.S. agricultural exports, according to the U.S. Department of Agriculture. Xi, who is expected to become president next year of the world's most populous nation, climbed into the cab of a John Deere tractor at a 4,000-acre farm near Des Moines and chatted with fifth-generation farmer Rick Kimberley. He asked detailed questions about farming techniques in Iowa, the nation's largest producer of corn and soybeans. He said the tractor really felt comfortable. He really enjoyed that," Kimberley said after the visit. It was a reunion of sorts for Xi, who nearly three decades ago visited Iowa to study agricultural techniques and learn about corn production. He'd insisted on the stop in Iowa, and the farm visit capped the Midwest leg of his visit to the United States. Xi's visit to Los Angeles is a reminder of his country's huge footprint at the busiest port in the United States. Nearly 60 percent of the imports moving through the Port of Los Angeles come from China, including $120 billion worth of computers, TVs, sneakers and other goods last year. The visit comes at a politically challenging time in U.S.-China relations, with the White House sending stern messages on currency and trade policies and Republican presidential candidates claiming President Barack Obama isn't doing enough to keep America competitive with the Chinese economy. The Asian power sells four times as many goods to the U.S. as the United States sends in return to China. The U.S. shipped $13.5 billion in exports to China through the Los Angeles port last year. In a carefully scripted event, Xi took a short walking tour through the China Shipping terminal with Brown and Mayor Antonio Villaraigosa. The facility sprawls over nearly 100 acres. "We're not just growing our ports, but we're greening our ports," Villaraigosa told Xi. "When I heard that this is an environmentally friendly green port, I felt that this was a major achievement," Xi replied. This is a solid foundation for future U.S.-China trade and economic cooperation. China has been the United States' fastest-growing export market, according to Kenneth Lieberthal, director of the John L. Thornton China Center at the Brookings Institution. I assume he'll stress this is a two-way street. This is of enormous benefit for both sides," Lieberthal said. Brown, a Democrat, said he wants to foster the state's relationship with China's next leader and encourage foreign investment in the state. China has trillions of dollars in reserves and they're going to be investing that increasingly throughout the world. I would like to see some of that money come into California for productive investment," the governor told The Associated Press on Wednesday. Not everyone celebrated the vice president's arrival. The California Fair Trade Coalition, a San Francisco-based nonprofit that supports expanding trade while promoting economic justice, issued a statement calling on Brown to "address China's predatory trade practices." "The economic potential for trade with China is massive, but if they aren't forced to level the playing field, this can only be a losing proposition for U.S. workers," said coalition director Tim Robertson. Much of Xi's visit, which began earlier this week in Washington, D.C., has been focused on agriculture. The strategic cooperation agreement signed Thursday outlines mutual goals and responsibilities of each nation. "It charts the course and gives us a guiding document that we can reference and, over time, refine and improve," said Scott Sindelar, the agricultural minister counselor at the U.S. embassy in Beijing, who attended the Des Moines conference. According to the USDA, the value of U.S. farm exports to China supported more than 160,000 American jobs last year across a variety of business sectors. U.S. Secretary of Agriculture Tom Vilsack said the two nations will have to work together to help feed a growing global population. We have the responsibility and opportunity to work together to address the causes of global hunger that effect more than 925 million people. Current populations trends mean that we must increase agricultural production by 70 percent in the year 2050 to feed nearly 9 billion people," he said.