NEW YORK ( TheStreet) -- When it comes to determining which way the market is headed, Jim Cramer told the viewers of his "Mad Money" TV show that "China is in charge." He said that China is the prism through which all of your market decisions must be made, and it just so happens that China has just created a huge opportunity in the fertilizer sector. Cramer said when it comes to commodities like steel and copper, corn and fertilizer, the U.S. is no longer in control. It's China that decides whether these commodities go higher or lower. It wasn't too long ago, he said, that China used 10% of the world's copper, while the U.S. used 30%. Today, that number is reversed.