The case for static range nitrogen management in Idaho sugarbeet production

Authors: Tarkalson, David; Bjorneberg, David; OLSEN, DAVEY - Amalgamated Sugar Company; Rogers, Christopher

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Nitrogen (N) management is important in sugarbeet production because it affects yield and quality. As Northwest U.S. sugarbeet yields continued to increase over the preceding decades, crop response data suggested that the established and utilized yield goal N management (YGNM) method for determining N requirements was leading to the over application of N fertilizer. This paper evaluates N supply effects on sugarbeet yields from three studies from 2005 to 2021. The use of an alternate static range N management (SRNM) approach was compared to the historically used YGNM approach. Historical data (1977-2021) shows that the N supply needed to produce maximum yields is within a narrow range. The N supply range required to produce maximum root and sucrose yields was 197 to 231 kg N ha-1. Our analysis shows that over time the YGNM approach has increasingly over recommended N supply. Over 80% of fields in the Amalgamated Sugar Company (ASCO) growing area are over supplying N relative to the SRNM range. We recommend that SRNM (200 to 230 kg N ha-1) replace YGNM for sugarbeet production in the Northwest U.S.

Technical Abstract: Nitrogen (N) management is important in sugarbeet (Beta vulgaris) production because it affects yield and quality. As Northwest U.S. sugarbeet yields continued to increase over the preceding decades, crop response data suggested that the established and utilized yield goal N management (YGNM) method for determining N requirements was leading to the over application of N fertilizer. This paper evaluates N supply effects on sugarbeet yields from three studies (26 research site-years) from 2005 to 2021. The use of an alternate static range N management (SRNM) approach was compared to the historically used YGNM approach. Historical data (1977-2021) shows that the N supply needed to produce maximum yields is within a narrow range. The N supply range required to produce maximum root and sucrose yields was 197 to 231 kg N ha-1. Our analysis shows that over time the YGNM approach has increasingly over recommended N supply. At the 12 responsive site-years, the YGNM N recommendations supplied an average of 61 kg N ha-1 more than needed to maximize yield. Over 80% of fields in the Amalgamated Sugar Company (ASCO) growing area are over supplying N relative to the SRNM range. Data suggests N supply affects sugarbeet quality factors to a lesser degree than historically thought. Nitrogen supply did not affect root yields in 14 of the 26 site-years, likely a result of high in season N mineralization and other microbiome effects. We recommend that SRNM (200 to 230 kg N ha-1) replace YGNM for sugarbeet production in the Northwest U.S.