Sugar Beet Production Following Corn, BtRR Corn, Sweet Corn, Spring Wheat, and Soybean in South Central Minnesota.

Information about the effect of previous crops grown on nitrogen recommendations for optimum sugar beet quality and yield is limited in south central Minnesota.  Corn is grown as a previous crop on about 75 % of the sugar beet acreage.  The next popular previous crop is soybean at 15 %.  A study was established to determine the effect of previous crops of conventional corn, genetically modified corn for Bt and roundup ready, sweet corn, soybean, and spring wheat on N required for optimum sugar beet yield and quality.  This study was conducted at three locations from 2006 to 2008.  The previous crops were grown in year one and fertilized using University of Minnesota fertilizer recommendations.  Sugar beet was grown in year 2 where each previous crop was grown in year.  The previous crop plots were split and six nitrogen rates (0, 33, 67, 101, 134, and 168 kg ha^-1) were applied.  In 2006 and 2007, root yield and extractable sucrose per acre was affected by the previous crop and nitrogen application.  Corn and genetically modified corn had the lowest root yield and extractable sucrose.  Spring wheat had the greatest root yield and extractable sucrose per acre in each year.  The previous crop did not affect the optimum nitrogen application rate.