Rate and time of nitrogen fertilizer application for winter camelina

Authors: GREGG, STEPHEN - University Of Minnesota; STROCK, JEFF - University Of Minnesota; Gesch, Russell - Russ; COULTER, JEFF - University Of Minnesota; GARCIA Y GARCIA, AXEL - University Of Minnesota

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2024
Publication Date: 6/5/2024
Citation: Gregg, S., Strock, J.S., Gesch, R.W., Coulter, J., Garcia Y Garcia, A. 2024. Rate and time of nitrogen fertilizer application for winter camelina. Agronomy Journal. 1-13. https://doi.org/10.1002/agj2.21610.
DOI: https://doi.org/10.1002/agj2.21610

Interpretive Summary: Winter camelina can help diversify the Midwest corn-soybean rotation while being grown as an "off-season" crop between corn and soybean. Camelina is a relatively low input crop. However, prior to this study, nitrogen fertilizer rate and timing of application (i.e., fall versus spring application) had not been optimized for winter camelina production. This study was conducted over two growing seasons at three field locations in Minnesota to determine the optimum nitrogen fertilizer rate and application timing for winter camelina. To test time of application, a split application was made by applying 1/3 of the nitrogen in the fall at planting with the remaining 2/3 applied in the spring, whereas for the spring application treatment, all the nitrogen was applied in the spring while plants were still in the rosette stage. Results demonstrated that winter camelina productivity was not significantly impacted by whether a split application of nitrogen was made in fall and spring, or if the nitrogen was all applied in the spring. Although seed and biomass yield increased with nitrogen rate up to 100 kg/ha, yields were not significantly different than those at 67 kg/ha of nitrogen. Findings suggest that 33 to 67 kg/ha of nitrogen fertilizer be applied in the spring to maximize winter camelina yield. This will reduce the potential of unwanted loss of nitrogen as nitrate, thus helping to improve water quality. Results will benefit ag professionals including growers looking to improve nitrogen fertility management for winter camelina.

Technical Abstract: Winter camelina [Camelina sativa (L.) Crantz] is a potential third crop to diversify maize (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotations in the upper Midwest. Although generally considered a low-input crop, empirical evidence suggests that it responds to added nitrogen (N). However, its optimum N rates have not been extensively studied in the region. A study was conducted from fall 2018 to fall 2020 to assess the effects of N fertilizer application strategies (fall-spring split versus spring only application) and rates on the growth, grain yield, and quality of winter camelina. Fertilization strategies did not affect yields. Both biomass and grain yields were greatly affected by N rates at all locations. Nitrogen had minimal effects on the oil and protein content of grain, although higher N rates were associated with a slight decrease in oil content and a slight increase in protein content. The number of branches and silicles per plant varied significantly with different N rates in all locations. Moreover, the seed:shell ratio showed significant differences in two out of three locations. Our findings suggest that a fertilization rate ranging from 33 to 67 kg N ha-1 is likely to maximize winter camelina grain yield under conditions in the region. This study provides important insights into the response of winter camelina to N fertilization, paving the way for the development of strategies to optimize grain yield and reduce environmental degradation, which can guide informed decisions about the integration of winter camelina into maize-soybean rotations in the region.