Herbage accumulation, nutritive value and nitrogen dynamics of a tall fescue forage system with either nitrogen fertilization or intercropped sunn hemp

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Elevated temperatures and declining precipitation during the summer results in tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. Cons] forage systems limiting cattle production. Multiple solutions have been explored to help relieve the stress on the system. Sunn hemp (Crotalaria Juncea L.) is an annual warm season legume that has potential to fill the production gap within tall fescue systems. The objectives of this project were to alternative solutions to increase tall fescue forage system productivity and nitrogen dynamics during the summer and fall of a tall fescue system when sunn hemp is intercropped. Results from our first experiment suggested that nitrogen fertilization resulted in the greatest forage nutritive value, herbage accumulation, and animal carrying capacity compared to intercropping sunn hemp and zero additional nitrogen system. The incorporation of sunn hemp resulted in greater forage nutritive value, herbage accumulation, and animal carrying capacity compared to an unfertilized tall fescue system, but not to the magnitude of nitrogen fertilization. Results from our second experiment suggested that intercropping sunn hemp resulted in tall fescue accumulating 25% of its nitrogen from the atmosphere. Based on our third experiment, residual nitrogen from intercropped sunn hemp resulted in limited spring regrowth in a tall fescue forage system.