Pricing weakness in Commodities?

A story from Barron's:

In recent weeks, prices for several commodities from soybeans to sugar have stalled. Cotton scored a massive bearish technical reversal last week. And in the stock market, fertilizer and copper stocks have been acting poorly.
Fertilizer stock CF Industries Holdings (NYSE: CF - News)was a market leader for much of the past eight months, but last week started to act rather poorly (see Chart 1). While the broad market edged higher it started to move lower with a particularly bearish performance February 18.