Below is a 1hr chart portraying the trade action for DEC16CORN (ZCZ2016 contract traded in Chicago).  U.S. corn prices for the December contract was unable to break below support at $3.33, since the beginning of August, and has since followed a short term rally as shown in the graph below.  Nearby support is seen at $3.40 (upward trend) and $3.33 whilst nearby resistance is  seen at $3.46