No abstract

Dallisgrass (Paspalum dilatatum) is well adapted to the Black Belt physiographic region of the southeastern United States, and information on its productivity and nutritive quality as influenced by grazing management is needed. In a 2-yr grazing experiment, replicate 0.40-ha paddocks in established dallisgrass pasture were continuously stocked, or replicate 0.40-ha paddocks were subdivided into two 0.20-ha (RS2), three 0.13-ha (RS3), or four 0.10-ha (RS4) cells and rotationally stocked with yearling beef steers. Individual cells within the RS2, RS3, and RS4 treatments were stocked for 7 d followed by 7, 14, or 21 d of rest, respectively. In 2007, 3 Angus × Simmental crossbred steers (initial BW, 354 ± 6 kg) were assigned randomly to each paddock on July 16; in 2008, 3 Angus × Simmental crossbred steers (initial BW, 310 ± 6 kg) were assigned randomly to each paddock on July 14. In 2007, there was no effect (P = 0.25) of stocking treatment on ADG. Steers grazing RS4, RS2, and continuously stocked paddocks had 106 (P = 0.01), 86 (P = 0.03), and 83 (P = 0.03) kg greater total BW gain per ha, respectively, than steers grazing RS3 paddocks. In 2008, there were no differences among treatments in ADG (P = 0.43) or total BW gain per ha (P = 0.90). Correlation and regression analyses revealed positive associations between steer performance and forage concentration of CP, areal mass (kg/ha) of forage DM, and areal mass of forage CP. Results indicate that productivity and quality of dallisgrass for stocker cattle production were comparable between continuous and rotational-stocking methods.

Dallisgrass (Paspalum dilatatum) is well adapted to the Black Belt region of the southeastern US, and information on its productivity and nutritive quality as influenced by fertility is needed. In each yr of a 2-yr study, an existing dallisgrass pasture that had been subdivided into 48 plots of 9.3 m 2 each was fertilized with the equivalent of 34 (34N), 67 (67N), 101 (101N) or 134 (134N) kg N/ha from poultry litter (PL) or commercial fertilizer (CF; NH 4 NO 3). In both years, primarygrowth and vegetative regrowth forage was harvested in mid-August and late September, respectively, and forage from each harvest was clipped to either a 5-or 10-cm stubble height. Forage cut to a 5-cm height yielded 71% more (P < 0.001) DM than forage cut to a 10-cm height, but forage dry matter (DM) yields were not different between CF and PL treatments across years and fertilization rates. Concentration of crude protein (CP) was greater (P = 0.002) for CF than PL forage and increased for both fertilizer sources with increasing rates of N application. Forage concentrations of cell-wall constituents were not different between CF and PL treatments. Forage amended with CF had a higher concentration of Ca, Mg and Mn than PL-amended forage; however, forage amended with PL had a higher concentration of P and K than CF-amended forage. There was no effect of fertilizer source on forage concentration of Al, Cu or Zn. Results indicate that PL and CF were comparable for supporting productivity and nutritive quality of dallisgrass on Black Belt soils.