Recent work has demonstrated the potential of using warm season grasses under high N fertilization for reducing excess soil P on dairy manure-impacted sites. The ancillary question arises as to what point of diminished soil-P status does forage production become negatively impacted? This research determined the factorial effects of N (67, 90, and 134 kg ha^-1) and P (0, 5, 10, 20, and 40 kg ha^-1) fertilizer application rates on the yield and nutritive value of bahiagrass (Paspalum notatum), stargrass (Cynodon nlemfuensis) and limpograss (Hemarthria altissima). Bahiagrass seasonal forage dry matter (DM) yield and tissue P concentration (10.6-11.5 Mg ha^-1, 1.8-2.2 g P kg^-1) were least, and limpograss yield and tissue P (4.2-7.7 Mg ha^-1, 0.9-1.7 g P kg^-1) were most impacted by changes in P fertilization rate. Increasing N fertilization rate beyond the UF/IFAS standard recommendation of 67 kg N ha^-1 had little effect on DM yield, in vitro organic matter digestion or tissue P concentration but increased forage crude protein concentration in all grasses. The data supports our earlier findings that bahiagrass offers the best choice for P phytoremediation whereas Limpograss is the most sensitive to P deficiency.