Improving Nitrogen Management in Pacific Northwest Sugarbeet Production

Abstract

Nitrogen management is critical in sugarbeet production to optimize yield and quality. Although, past research has been critical to improving sugarbeet nitrogen nutrition, continued research is needed to evaluate evolving varieties and management practices. From 2005 to 2010, studies from 14 locations were conducted by agronomists from The Amalgamated Sugar Company and scientists at the USDA-ARS Northwest Irrigation and Soils Research Laboratory to evaluate the effect of N supply (fertilizer N + N in soil) on sugarbeet production in the Pacific Northwest. At each location, the effect of various levels of N supply on estimated recoverable sucrose yield, root yield, sucrose concentration, brei nitrate concentration, and nitrogen use efficiency were assessed. Nitrogen supply significantly affected estimated recoverable sucrose yield for 6 of the 14 locations. For the 8 non responsive sites, the maximum estimated recoverable sucrose yield was assumed to be the lowest N supply. The average nitrogen requirement at maximum estimated recoverable sucrose yield across all site-years was 2.25 kilogram nitrogen per megagram of beet yield and ranged from 1.4 to 3.7. Thirteen of the 14 locations had a nitrogen requirement at or below 2.8 kilogram nitrogen per megagram of beet yield, substantially less than current recommendations of 3.5 to 4.0. Nitrogen requirements can be reduced in the Pacific Northwest sugarbeet production area compared to past recommendations resulting in reduced N fertilizer applications and significant cost savings.