FALL MANAGEMENT EFFECTS ON GRASSLANDS-MATUA PRAIRIE GRASS PRODUCTION AND SWARD CHARACTERISTICS

Ruminant animal production costs in the northeastern USA can be lowere d by extending the fall grazing season. Two field experiments were ini tiated with prairie grass [Bromus unioloides (Willd.) H.B.K.cv. Grassl ands Matua; syn. B. willdenowii Kunth] to determine effects of fall ma nagement (i.e., clipping) on forage production and winter survival. Pl antings were made in May 1986 for Exp. 1 and June 1990 for Exp. 2. Exp eriment 1 addressed date of fall harvest and residual stubble height e ffects on fall yields and tiller density, winter survival, and spring yields and tiller density. Experiment 2 addressed the interaction of h arvest frequency and residual stubble height on the same parameters as for Exp. 1. Fall yields of Matua peaked at 4.0 Mg ha(-1) in late Octo ber to early November (Exp. 1 and 2). Mean fall yields were reduced 20 , 40, and 60% as residual stubble height was increased from 7.5 cm to 12.5, 20.0 or 25.0 cm, respectively (Exp. 1). Spring yields were high from plots clipped to a 7.5-cm stubble in September and decreased as f all han-est was delayed to November (Exp. 1). Spring yields from plots clipped to a 7.5-cm stubble in late November were only 20 to 25% of y ields from plots clipped in September. Leaving a higher residual stubb le in fall compensated considerably for the deleterious effect of harv esting in late fall. Clipping to a 20.0-, :12.5- or 7.5-cm stubble in fall resulted in linear decreases in spring yields as fall harvest was delayed from September to November, and clipping to 25.0 cm gave a qu adratic response, with a peak at mid-October. Matua plots that were ha rvested once in late fall or not at all (check) recovered very slowly in spring and had a lower yield potential than plots that had been har vested two, three, or Pour times in fall. To optimize production of Ma tua in fall and spring it is recommended that one slimmer rest period be extended to allow natural reseeding and that two or three fall harv ests or gratings be taken to increase stand density and winter surviva l.