Initial insights into sunn hemp–corn intercropping for forage production and nitrogen reduction

Authors: SIMILI, FLAVIA - University Of Florida; DUBEUX, JOSE - University Of Florida; Jaramillo, David; QUEIROZ, LUANA - University Of Florida; BRETAS, IGOR - University Of Florida; LIRA, MARIO - University Of Florida; RUIZ-MORENO, MARTIN - University Of Florida; ACUNA, JAVIER - University Of Florida; TRUMPP, KEVIN - University Of Florida; Akins, Matthew

Submitted to: Annals of Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2026
Publication Date: 3/19/2026
Citation: Simili, F., Dubeux, J., Jaramillo, D.M., Queiroz, L., Bretas, I., Lira, M., Ruiz-Moreno, M., Acuna, J., Trumpp, K., Akins, M.S. 2026. Initial insights into sunn hemp–corn intercropping for forage production and nitrogen reduction. Annals of Agricultural Sciences. https://doi.org/10.1002/agg2.70338.
DOI: https://doi.org/10.1002/agg2.70338

Interpretive Summary: Corn is an important crop for grain and silage production for livestock systems. However, corn production generally requires high levels of nitrogen fertilizer inputs. Introducing sunn hemp, an annual legume, can be a potential option for reducing nitrogen inputs and sustaining biomass production. The aim of this study was to produce biomass for silage and minimize nitrogen fertilizer use by combining sunn hemp and corn. Sunn hemp was intercropped with corn in two locations, Marianna, Florida and Marshfield, Wisconsin. The results showed that intercropping sunn hemp and corn can be a strategy for improving nitrogen use efficiency of a give production system. However, sunn hemp reduced the overall biomass accumulation when intercropped with corn. Further management strategies are needed to evaluate ways of introducing sunn hemp with corn silage production. The data obtained in this study is of interest to crop and livestock producers evaluating strategies to reduce nutrient inputs and identifying strategies to improve crop productivity.

Technical Abstract: Corn is a globally important crop for grain and silage production for livestock systems. However, corn generally requires high levels of nitrogen (N) fertilizer. Introducing sunn hemp (SH), an annual legume, is a potential option for reducing nitrogen inputs. The aim of this study was to produce biomass for silage and minimize nitrogen fertilizer use by combining SH and corn. Sunn hemp was intercropped with corn in two locations (Marianna, FL and Marshfield, WI). Treatments were: SH monoculture (SH), corn without N-fertilizer (Corn-N), N-fertilized corn (Corn+N), corn and SH planted on the same day (Corn+SH0), corn and SH planted four weeks later (Corn+SH4). Corn+N had greater herbage accumulation in both sites. The treatment SH fixed 87 kg N/ha and had greater %N derived from the atmosphere (%Ndfa) in Marianna (71.4%). Nitrogen yield was greater for Corn+N in both sites, and no difference was found between the intercropped treatments. Corn+SH0 in Marianna and Corn+SH4 in Marshfield resulted in great N use efficiency (NUE) (72% and 69%, respectively). The data indicate that combining corn and SH enhances NUE. However, intercropping corn and SH reduces the overall biomass accumulation, which requires further evaluation to promote producer adoption of these systems.