By Dan Kaiser
I have received a few questions this spring regarding nutrient management considerations for fields with unharvested sugarbeets. The main question is whether the sugarbeets left in the field could provide a potential nitrogen (N) credit for this year’s crop. The issue this spring seems to be directed towards the northwest Minnesota growing region, and the answer on what to do is a bit more complicated with more crops potentially being grown in 2024. However, here are a few key takeaways.
Can you take a nitrogen credit?
While many would consider there to be some potential for additional N availability, there is no credit given to the unharvested portion of the beet. Beet tops alone might provide an N credit to next year’s (2025’s) crops depending on how green the beets were when the tops were removed. However, the decomposing root can actually tie up nitrogen for the 2024 crop, so adjustments may need to be made where N rates are increased for 2024.
It is generally recommended that soybean be grown in fields with unharvested sugarbeets from the previous year as soybean does not require additional nitrogen to be applied. I won’t go into specific details on the exact amount of N that can be tied up by decomposing sugarbeets as that information is covered in the links below. However, an additional 30-50 pounds of N may be needed depending on the crop grown in 2024.
Should other nutrients be treated differently?
Phosphorus (P) can be an issue in fields in the Red River Valley but P management should not be changed based on whether sugarbeets were left in the field. Follow soil test recommendations of phosphorus as planned (Sugarbeet fertilizer guidelines for Minnesota). Increased deficiency of potassium or sulfur is also not expected.
Source : umn.edu