In 2023, on-farm trials were conducted in three Southeast Kansas counties under partnership between local producers and their respective Extension districts. The goal of these trials was to observe sunn hemp’s potential as a summer annual forage to supplement tall fescue pastures during the “summer slump.” If producers are able to provide high quality forage during the summer slump, less feed supplementation could be used and other tall fescue paddocks could be allowed longer rest periods.
Sunn hemp (Crotalaria juncea L.) is an annual, warm season legume native to India. It has traditionally been used as a fiber crop, but it has gained popularity in the United States as a cover crop.
Recent studies from Missouri University have shown sunn hemp to be a productive annual forage option that is high in protein and carries negligible bloat risk.
Sunn hemp was drilled into long-time tall fescue pastures at rates of 30 pounds an acre. After planting, roughly 90% emergence was observed. By July, the stand had decreased to roughly 50% due to drought.
Plots were harvested the first week of August. Crude protein was found to be 2-5% higher in samples containing sunn hemp. This increase in crude protein was enough to meet a cow’s needs without supplementation. Total digestible nutrients (TDN) also showed a 2-3% increase in samples containing sunn hemp.
Water was a limiting factor throughout these trials, but sunn hemp shows potential to be a high-quality alternative forage to interseed into tall fescue pastures. Sunn hemp was broadcast into others areas, but the sunn hemp did not emerge, therefore, drilling sunn hemp is recommended.
A full study report will be coming out soon.
