Oct. 28 (Bloomberg) — Sociedad Quimica y Minera de Chile SA, Chile’s biggest fertilizer producer, tumbled to the lowest price in seven weeks after reporting a 57 percent drop in third-quarter profit.

The Santiago-based company, known as Soquimich, retreated 2 percent in Santiago trading to 19,470 pesos, the lowest since Sept. 7. The shares have fallen for seven straight days, losing 9 percent this month.

Net income fell to $82.3 million from $191 million a year earlier, Soquimich wrote in an e-mailed statement distributed after markets closed yesterday. Potassium-related fertilizer prices in the second half are down on first-half levels and average prices for all products probably will be lower, Chief Executive Officer Patricio Contesse wrote in the statement.

“China and India are the biggest consumers of potash so the prices they set become a reference for the market,” Juan Carlos Parra, an analyst at CorpResearch SA, said today in a telephone interview from Santiago. “The fact that the Chinese haven’t set their prices yet leaves open the possibility that prices will fall even further.”