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The effect of fertility on the yields of native perennial grasses was investigated in pot culture and field experiments. Yields of six native perennial grasses and Paspalum dilatatum Poir were determined in the glasshouse at five levels of applied phosphorus (P), sulphur (S) and nitrogen (N) and in the field the biomass of individual tussocks of eight native grasses was compared. In pot culture the maximum yields of the native perennial grasses with P, S and N applied were 15 to 75% lower than those of P. dilatatum. Within the native grasses there were significant yield differences: Bothriochloa macra (Steud) S.T. Blake, Chloris truncata R.Br. and Dichanthium sericeum (R. Br.) Camus yielded up to twice as much dry matter as either Aristida ramosa R.Br., Sporobolus elongatus R.Br. or Eragrostis leptostachya Steud. These data indicate that P, S and N are all essential for maximum yield of some native grasses, and large imbalances in the level of these nutrients resulted in seedling mortalities in most native grasses.