Understanding availability and loss potential of nitrogen for varying topsoil depths of poorly-drained claypan soil landscapes could help producers make improve decisions when managing crops for feed grain or bio-fuels.  While it has been well documented that topsoil depth on these soils plays an important role in storing water for crop growth, it is not well known how this same soil property affects N loss for growing seasons that are abnormally wet, such as the case in 2009 for much of Missouri.  This study was conducted to evaluate the influence of claypan soil depth on nitrogen loss on corn grain production, primarily attributed to de-nitrification.  In order to understand this relationship, nitrogen recovered in grain and stover, grain yield, and SPAD chlorophyll meter readings were taken from corn grown on a range of topsoil depths (0 to 50 cm) and fertilized with 167 kg N/ha.  Observations during this growing season showed that nitrogen stress to corn crop increased as topsoil depth decreased.  Further analysis will be done to show the percent reduction as a function of topsoil depth.