Sugar Beet Production Following Wheat, Corn, and Soybean in the Red River Valley.

Sugar beet in the Red River Valley of the North has traditionally followed a small grain crop.  In recent years, corn and soybean production has increased 2 to 5 times while spring wheat production has declined.  Currently, it is acceptable to grow sugar beet after spring wheat or corn, but not after soybean. Previous research has shown negative effects of corn residue on sugar beet that was not corrected with nitrogen fertilizer (N).  Field experiments were designed to examine the effects of a previous crop of spring wheat, corn, or soybean on sugar beet production.  A second objective was to determine if primary tillage after the previous crops harvest (moldboard plow or chisel plow) or N fertilizer would overcome potential negative effects of previous crop.  Regardless of previous crop, primary tillage had no effect on sugar beet production.  Nitrogen rates affected sugar beet yield and quality, but it varied with previous crop.  At all N rates, sugar beet root yields were greater following spring wheat and least following corn.  Additional N did not overcome the negative effect of corn.  Soybean as a previous crop had intermediate effects on sugar beet root yield at all N rates.  Some N fertilizer was needed to maximize sugar beet root quality (recoverable sucrose per ton of beet) when grown after corn and soybean, but not following spring wheat.  However, after a critical N rate was reached, the decline in root quality was greater following soybean than other previous crops.  Sugar beet performed best when grown after spring wheat.  Sugar beet performance after soybean was not as great as following wheat, but was better than following corn.  Growers are cautioned that root rot disease issues growing sugar beet after soybean may exist.