U.S. agriculture is facing major shifts in trade relationships, global demographics and demand patterns that will impact how farmers grow and sell their products, according to Todd Thurman, an international agricultural consultant. 

Despite its history as a dominant importer of U.S. soybeans and pork, China’s demand for agricultural imports is waning due to its rising economic challenges and drastic population decline, said Thurman, founder of Swine Insights International. He has spent 13 years...