Response of Texas bluegrass to season of nitrogen fertilization on the Louisiana Coastal Plain

Texas bluegrass (Poa arachnifera Torr.) has shown potential for use as a co ol-season perennial pasture grass in the southern Great Plains, where it oc curs as a natural component of rangeland plant communities, and into the we stern Coastal Plain. Responsiveness of this grass to nitrogen (N) fertiliza tion appeared to be limited to the spring growing period in initial evaluat ions in Louisiana. A field plot experiment was conducted to assess forage p roduction and quality responses to season of N fertilization on the Syn-1 p opulation of Texas bluegrass. Winter forage production responses to 50 kg N ha(-1) were obtained in the 1997-98 growing season but not in 1998-99 afte r stands had been depleted by summer drought. Greatest yield increases resu lted from spring N application, however, fall plus winter fertilization pro vided the most uniform distribution of forage through the cool season. Fora ge fiber fractions, in vitro digestibility, and crude protein were not affe cted by N fertilization. Both amount and distribution of Texas bluegrass fo rage, but not forage quality, can be manipulated by time of N fertilization .